Okay, I just typed up a much better response and then lost it into the Lemmy void, so sorry this will be much more to the point.
You are arguing two sides of the same issue based on your own personal opinions on each one. The issue being that people have certain psychological or behavioural issues. One: people who feel the need to leave a note on edited posts are paranoid. Two: people get upset by the number of downvotes.
First, I think your assessment about why people leave a note about their edits is incorrect. Even if they are doing it because they are paranoid, they should try to overcome that and possibly seek real world help. It is also such a minor thing that we should not try to create some "internet law" to justify criticizing them.
Second, if someone is getting that upset over downvotes, they should try to overcome that, and definitely seek real world help if they cannot cope. Being their gatekeeper will not solve any of these underlying problems and will not stop people from being negative. Again, instance admins can disable downvotes, so this is a non-issue with Lemmy.