„Outsider“ (as you put it) is not providing anything we need (we need current data, not historical one; current translations to a lot of languages for placenames can easily come from wikipedia/wikidata which we already have, so adding them is redundant even more than name:lt tag is).
„Outsider“ is just knowingly ignoring our rules.
In the end you get a data subset which does not represent neither current Polish names, nor historical Polish names of specific period. So this dataset cannot be used for any of such purposes, so it is useless...
But once again, do what you want. I will fix your errors but I will not guard the data against fixes of name:pl values by other mappers.

As wmyrda has pointed out, he is taking a map from 1928-1939 and trying to map what he sees there to todays villages. Both mapping such different things as well as putting names from that map is incorrect. If his purpose is solely to use that old map to get Polish names - then he is using bad source. If he wants to put information of that historical map to some GIS DB (in this case OSM), then he is putting data into wrong place because that data will divert from his hard work really fast.
But that is your choice. I've spent too much time on this pointless topic already.

And main point. Please respect a strive of Lithuanian mappers for as higher quality as possible and not look at it as "it's your choice, so you fix what we brake".
This adding of name:lt tag has already proven very useful when crap.me users started destroying good data as well as in other less widespread examples.

1. Yes, there is only one official language in Lithuania - Lithuanian (85% of population are Lithuanians, so there is no point of having other official language).
2. This discussion takes too much time already. This is very old keepright rule and I did not invent/write keepright. We stress on QA very much and there is no other way to handle it without using automated QA tools. I guess we should now concentrate on should such historical data be added to OSM database at all.
3. One of Lithuanian mappers was doing similar hard work putting Lithuanian names in Karaliaučius (Kaliningrad) district. Later when local (Russian) mappers found that out they also changed lots of the names so part of his hard work was lost. He then created a separate dataset and published it separately. This situation looks very similar. Therefore my advice is to add such historic names to a different dataset, because name:pl tag is definitely not the right place to put HISTORICAL names (why start of XX age is chosen?, why not XVIII age, or second Moscow occupation (soviet) period? Answer is not needed, I'm just giving examples to show that there is no one correct answer). So I'm now stressing the point that this hard work of going through historical maps and mapping names to existing objects is sometimes incorrect (villages change quite a lot) and is in danger of being destroyed by other mappers doing legitimate/correct editions.

1. You're doing work which belongs to OpenHistoricalMap, not OpenStreetMap. This explains why some of the name:pl tags you add are incorrect: they have nothing in common with official name, neither phonetically, nor by the meaning. While I'm not interested in name:pl tags, expect those to be fixed by other mappers.
2. Administration division changes, you cannot map (connect) every historical village/town to village/town existing today. Places get abandoned, merged and renamed because of different reasons including vote of people living in the village.
3. If you think that your hard work is for some reason more valuable/important than my hard work, then please contact DWG BEFORE doing any changes and requiring any fixes. Lets get third party opinion about 1) adding OHM data to OSM 2) knowingly introducing errors and ignoring local mappers.

@rmikke:
I cannot expect outside mappers to know it in the beginning. And that is why I have already fixed hundreds of such errors in the past (sometimes they came together with adding some old incorrect population or other incorrect data etc., I had to revert such additional bad changes, bot would not have been able to do that without removing name:pl tags). But it was taking too much time, so after I told/explained it NUMEROUS times to the user doing the changes, I expect that such a simple rule is respected. It is not a rocket science to add ONE tag when adding another. As the change is very simple, I count ignoring it as total disrespect of Lithuanian mappers work on keeping the data clean, predictable and usable.
And it is not blackmailing, it is showing that rude ignorance of now KNOWN local rules is far from "doing a good job". If somebody keeps their house clean, it is not polite for the outsider to walk inside with dirty boots and tell "just buy the cleaning service".

Keepright or no, this is almost ten years old rule how name:* tags work. Keepright is just one of QA tools which checks it.
There is enough material explaining what is the purpose of name:xx tag and this is not the right place to discuss it.

OSM spirit says that you must consult and take into account the local mapping rules. Local mapping rules in Lithuania is to do QUALITY work, not anything anyway someway anyhow. You KNOW the rules, you know what you must do, it is not hard to do that, and yet you say you will do it in incorrect way. How do you expect such behaviour to be valued?

In Lithuania ALL values in name tag are Lithuanian. So if the point you're changing is in Lithuania, name tag HAS Lithuanian value.
Let's not get into situation where I would think of doing reverts rather than spending hours fixing name tag errors done on purpose.
Do it RIGHT or don't do it at all.

Chrm. You're updating not 10-20, but hundreds objects and I have to spend too much time fixing it. It is not nice, that you're knowingly introducing a lot of errors. Please fix your automated script if you want to do more automated updates. The rule is very simple: if area is in Lithuania and name:lt does not exist, add name:lt with value equal to name value. Thank you.

I probable have never changed any placename with old_name tag. But if I do, I will only change name tag and leave old_name (and old_name:pl) as is.

OK. But just for your information: in Lithuania all place names and population are checked/compared to official placename registry (new placenames appear, old ones disappear monthly). So in Lithuania all placenames have name tag in Lithuanian.

Fixing errors which different QA tools (including keepright.at) finds.
The rationale of having name:xx has been discussed a long time ago. Problem with "name" tag is that it is not clear in what language the name has been entered. Even in countries like Poland or Lithuania where there is only one official language, name tag sometimes contains non "local" values. But in some other countries there is more than one official language.

This was one of keepright.at checks from looong time ago...

Please add name:lt with value equal to name when adding other name:* tags (one of keepright.at errors). Thank you.

Na, jei tikrai taip yra, tada gerai. Nes, kiek rašė OsmAnd naudotojai, jiems POI reikia ANT kelio.

Bet ar į tą šalia kelio esančią kamerą, kuri niekaip nesujungta su keliu, reaguoja (parodo įspėjimą apie kamerą) nors vienas maršrutizatorius? Mano žiniomis ne, bet aš į kamerų žymėjimą per daug nesigilinau, tai galiu klysti.

Ar tikrai gerai pašalinta kamera? Nes išimta iš kelio, todėl maršrutizatoriai nebežinos apie šitą kamerą.

Pakeitimas atšauktas. Namo pozicija yra ten, kur yra namo pagrindas, o ne kur ortofotografijoje matosi stogas.

Reverted