I see 2 (non-shady) reasons why it got deleted: a) the spelling error got fixed so, there is no need in that thread anymore. b) it was written in russian and as it often happens with any non-english topics they do get deleted sometimes.

Maybe he deletes them because they got fixed?

Bug Report was written in russian be someone in february. At march developers confirmed that bug. I buyed the game in June and there wasn't any fixes and patches from start oh the year. After asking in twitter, developer just delete all threads abot bugs - another was written in english and confirmed too.

Then why there's not a lot of negative reviews mentioning that?
Developers can't censor or delete reviews.

1. The spelling error was on the store page, no patch was required to fix it.
2. The thread was not deleted, it was moved from general discussions to a sub-forum specifically for bugs.
3. The OP of this post complained on twitter and on the forums about something that was fixed within days of it being noticed.
4. The developers of Paperbark are really cool and decent people, you should check out their game and ignore this guy.

Сan you post the link to the moved thread please? I have old link from twitter and this link was broken - I can't find this thread now.

Even the link on your twitter still works.
Edit: The Bug Report section maybe restricted to game owners only which is why the link still works for me, but not you.