The new Meta rules have a carve-out that allows allegations of mental illness and abnormality based on gender and sexual orientation, but no other reason.

You’re seemingly making the argument that this is good because those allegations are statistically popular.

If you support freedom of speech, shouldn’t all insults be allowed rather than just those targeted at a specific group?

Unfortunately that is the position of many religious groups (including in the US) and populations in non-Western countries (e.g. Middle East).