Why is the user "Iváns" blanking many messages posted by other people in various talk pages?

Why is the user "Iváns" blanking now many messages posted by other people in various talk pages (related to translations in the Galician language, including for example replies made by "Elisardojm")?

See Special:Contributions/Iváns (note that the addition the "__NOINDEX" in his talk page header is OK).

Note that not just the contents of messages are cleared, their subject lines are now blanked as well (and in all messages and replies in these threads). Those are messages from people complaining about what Iváns did in Galician translations of MediaWiki, and asking him to discuss them on community pages of Gilician wikis. Blanking these messages seems futile as they are still in the history and these messages still dont not disappear from his talk page (they just look empty now at first glance).