Ok, I get it. We all love freedom of thought. 1984 world sucks. But there is room to say both 'you can think what you want as far as the law is concerned' and 'you should try to curtail rather than indulge peadophelic thoughts'. Noticing that it would be unhelpful to criminalise certain speech and thinking doesn't absolve us of interrogating why we think and say things, and is compatible with thinking that we should try to change our thinking. Not in some Orwellian government mandated programme, but from the type of consciousness raising that feminism is so very good at inducing.
To be clear: I don't think these guys should go to prison, or that we should legislate against them bringing sex masks into IKEA. I do think that it is morally wrong of them to subejct the public to their sexual fetish.
The law argument is too easy. Loads of shitty behaviour is legal, and rightly so. The real question is: why are they doing this? They are doing it because they are sexually gratified by bystanders seeing them engaged in a sexual kink. That is the reason. So now the follow-up questions are, is that the type of reason we want to be motivating behaviour? Why do they feel that is a good reason? The answer will be complicated, and for sure involve male sexual entiltement to female attention. The action is designed to not be liked, that's part of the motivation for it.