Added to Unbounded rules (this is a clarification not a change):
Do not be mean. Criticism should be aimed at truth and progress, not used as an opportunity to attack others.
If you think some criticism is mean or attacking, say so. If you don’t point out the problem, no one can clarify what they meant (you may not understand their point) or change their behavior. You can ask how something is meant to help or say what you don’t like. Don’t assume someone is being mean on purpose and silently judge them.