Committing a crime is not “speech”. Molesting minors is a crime.
If the wanted to make a case that it was “speech” they would have to take it to court, probably all the way to the SC and I’m pretty sure they would lose.
For example, you can talk about murder in general, how you’d like to murder (not a specific person but you just want to do it). You could even start up an organization of people who would like to murder people, or talk about murder in general, ways to do it etc. But if you ACT on it, then you’ve committed a crime and can be arrested and hopefully put away for life.
You seem to be begging the question. If you define a certain type of speech as a crime, than it’s not speech.
Is public nudity a crime? It is arguably “victimless,” and doesn’t cost anyone for it to be allowed. Forget the irrelevant arguments of “public health,” those are provably false. What if someone claims that walking in the nude down the street is their form of “speech?”