...but they can edit their responses...
Unlike for questions and answers, commentscomments only have a have very limited window (only 5 minutes) when edits are allowed. After that the only remaining "edit" option the system allows users is the delete button.
As a moderator I don't see any evidence that comments to your question have been deleted. I can only read the comments as they currently are, the same for you and everybody else.
I even had personal attacks on me.
I don't see anything that supports that claim, but please remember that comments are intended for short, terse and quick messages. They are not lengthy well-formatted answers. Please don't confuse any necessarily direct language for aggressive.