I don't see how there can be a more obvious expression of intolerance than straight up denying the very existence of people you hate.
Is it 'intolerant' to say 'white people can't be black'?
What do you mean by 'deny the existence of'? If I think 'male lesbian' is a contradiction in terms (and therefore there are no male lesbians), does that deny the existence of people who claim to be male lesbians?
The idea of "fake" men and women is more actively dangerous, as surprise at the revelation of someone's birth sex is a common motivator for the violent hate crimes that plague the trans members of the global community.
I have never seen any statistics backing up the idea that 'violent hate crimes' 'plague' trans-identified people. Do you have a source that identifies this 'plague'?
Finally, such views encourage misgendering of others.
I do not regard encouraging others to not participate in somebody's delusion a problem.