It’s for (often implicit) communities to decide; communities whose members share a certain set of norms.

Further, legality does not imply correctness.

For example, it’s probably legal to call somebody a transphobic slur in many parts of the world but to suggest that trans people shouldn’t attempt to avoid or “cancel” such people is ridiculous.

And if you sincerely think that the only acceptable action to take is make a petition to change the law, I would suggest you go out and touch some grass. The law doesn’t work that way.