So the other day I found out that some mappers where blindly merging nodes that should not be merged or worse, removing some nodes effectively truncating some objects.

I contacted some of the users but did not get a reply. They did not fix their mistakes leaving the map even worse than before their edits.

Some people pointed me to the mailing lists where I asked one particularly harmful changeset to be reverted but unfortunately nobody undid that particular changeset.

One of the persons doing the merges said he would stop. At least a positive point here.

But in the end several people ruined hours of my and probably others mapping time, they won't fix it and nobody seems to really care.

Yes it is a community and error happens but couldn't just people follow a minimum of rules (as in Automated edits/Rules of conduct), cleanup after their mess and follow the basic principle that "If it's not broken don't fix it".