As Prev said earlier, the issue isn't forbidding hate-speech, the issue is enforcing use of specific terms to describe something which isn't necessarily biologically true.
Enforcing use of language to suit a social trend is the authoritarianism part. Enforcing the disuse of hate terms to protect people is not. The concept of fluid gender identity is very young and itself fluid, making ever-changing amendments inevitable, which will only muddy the waters.
We both agree people are free to identify with whatever term or group they wish, and they should not be discriminated for it. But neither should they be able, by law, to force others to use their language. For people of dark skin I, for example, don't use the term 'people of colour' as not so long ago we were told 'coloured' was no longer acceptable (before that it was the polite accepted term). It's an ever-changing landscape and bully to those who want to play that game, but I don't and neither do the general populace.
Most people prefer not to think about a person's skin colour at all, and I thought we were almost there not so long ago. Same with gay/trans/etc...the internet is breeding specialist scenes which explode onto the mainstream. All fine and dandy until our language becomes enforced to fit the scene, which breeds resentment and rewinds social progress.
The point is by us not enforcing language of specialist scenes were are not discriminating against people, we still value them as people of equal worth to ourselves. But if we allowed the use of hate-terms we would be allowing discrimination, those terms clearly value the target as of lower worth. Not the same thing.
Have you heard of newspeak?
But it is not forcing anything. I've said this now a few times here. I can only repaste my post to Prevenger regarding the Canadian Bar Association and their views on the law. To quote them:
C-16 Will Not Impede Freedom of Expression. Recently, the debate has turned to whether the amendments will force individuals to embrace concepts, even use pronouns, which they find objectionable. This is a misunderstanding of human rights and hate crimes legislation.
More here:
https://www.cba.org/CMSPages/GetFile.aspx?guid=be34d5a4-8850-40a0-beea-432eeb762d7f