@DrPsyBuffy
Mastodon only shows you posts from the accounts and hashtags you're following. If you're unhappy with what you're seeing, you might want to review the recent posts from those people. Then you can unfollow the people whose posts are turning you off.
That being said, there is an old saying about group dynamics. "There's one a$$hole in every group." You may have to become a hermit if you want to avoid mean people completely.