It's not that different from refusing to use someone's pronouns. I think that both are a mean way to respond to a fellow human.
Maybe that's the bigger question here. Should language be precise, or nice? Or, to the extremes we're seeing here, should language be formed to make certain types of subjects difficult or impossible to present themselves? Maybe freedom of thought, and the ugliness beyond, is something that should only be allowed in ones own head?
I don't think that asking people to say "died by suicide" rather than "committed suicide" is a question of precision vs niceness. Both are plenty precise, we agree they describe exactly the same IRL event.
I also don't think that asking people to say "died by suicide" rather than "committed suicide" is an affront to freedom of thought, for the same reason.
That said, sure, yes, my parents always told me to "think before you speak" and sometimes "you can think it but don't say it". We all think things that we shouldn't say, usually because saying those things will hurt someone. If you insist on saying something after being informed that it hurts someone (e.g., not using their pronouns, or referring to a painful moment in their life [e.g. the suicide of a loved one] in a way that hurts them) then, yeah, that's kind of the thing my parents tried to teach me not to do.