However JOSM is the wonderful editing tool, but it couldn't be considered as a reference.
Please join to Iranin OSM group vie the following link.
They're usually talking in local Persian language, but there are some people who are able to talk to you in English.

https://t.me/joinchat/BP9kIj3PaK-pUEWi0Ne8tA

The group is in Farsi.
You said: "JOSM validator complains if there is name:lang tag matching name tag".
And Point No.2 emit this issue.

However if you think we're doing wrong, please provide a reference to explain the reason for this duplication and we will remove this part of automatic edits.
At the moment, I think there is no reason to put redundant/duplicated information.
But I and other Iranian editors do respect to the OSM rules.

The local language of this area is Farsi and the [name:fa] is a duplication of [name]. So it's unnecessary. Tag [name] refers to local language according to OSM wiki.
This automatic edit was discussed in Iran OSM Telegram Group.

برحسب اتفاق نودهایی که شما حذف کردید از چنجست اشتباهی بود که یکی از کاربران غیرعمدی اونها رو وارد نقشه کرده بود و خودش هم به دنبال حذف این چنجستها بود.

قسمت عمده ایمپورت اشتباه توسط شما و بقیه توسط چند کاربر دیگر و چند ربات تشخیص داپلیکیشن، حذف شده بود.
تنها ۳۳ آبجکت از ۶ چنجستهای اشتباه باقی مانده بود که من حذفشون کردم

با اجازتون همه چنجستهای اشتباه رو ریورت میکنم که اگر چیزی جا مونده باشه برگرده.