KJK isn't left wing. All KJK does is say sex exists and invite people to say how that fact (or the denial of) affects their lives.
The reality of sex is like the reality of money. For good or bad, it exists and that has a material effect on real people's lives.
An individual absolutely may or may not approve of it existing, may or may not believe it's a construct, may or may not accept the gender constructs society loads on top of that existence, and they have a right to each of those political views.
But nevertheless, sex as a physical difference, and as something with social consequences, does exist.
So yes, what that fact means for humans, and how society should deal with that, is absolutely political and could be different for people on the left and on the right. But the fundamental fact of sex is, or at least should be, as politically neutral as the fact of gravity.
Those who think that the simple recognition of sex as a real and pertinent factor in people's lives can be assigned as politically right or left need to take a step back and have a good think about how they came to that view and whether it genuinely reflects how people identity and how they live their lives.