I would say a lot of what Acquiesce has said here is true, it's not about anyone trying to deny someone their humanity. Yes that person who thinks he is a 6 year-old child is clearly on some other level and I would in no shape or form be comfortable being around him.
The issue for me comes in with compelled speech and being forced to change my biological understanding so that someone else can feel "comfortable with their own body". In Canada we had the liberal-left steamroll Bill C-16 which made it a criminal offense to not recognize peoples self-identification since it would be a "violation" of their human rights. Sure the case at hand would have to be extreme (I hope), in which this would ever be used as justification to hit someone with a criminal charge, but why is someones wish to be referred to as a false pronoun more important than ones integrity to be truthful?
Funnily enough a similar topic came up today in a discussion (in real life), where how excited would you be to know your SO wanted a sex change - surgery and all? Not only would this affect a sex life (important to a healthy relationship), but likely just end the relationship altogether. In extreme cases we see this with families as Acq pointed out where it is/would be horrible for a child to go through.
On top of that, this culture shift in "making it acceptable" is nonsense, kids are being talked into things well before they have even developed their sexual organs. I can understand to a degree of trying to teach kids about sex-ed at an earlier age as many education systems now are, but there is a line. Why are they also not being taught of the crazy high suicide rates? Is it in fear of deterring kids from this new cultural wave of "acceptance", or because they are just so misinformed? Here is a video:
https://www.youtube.com/watch?v=oTP4okl0gUk , a complete joke in my opinion, showing how far things have gone. Kids should not be taught these things at such an age, period.
I'm not even getting into issues with athletes and how it ruins the integrity of sports, or literally the many other reasons why this social-political wave is going to far. You do what you want, but the moment you try and make your life decisions a hassel in my life (ie. through compelled speech) is where I have a problem.