Thats because people on the left keep bringing birth defects and other rare illnesses into the argument. People with the XX chromosomes, people born with a vagina, people who can have babies, people who have a period through most of their lives etc are all correct. 

Yes I guess definitions are really easy to create if you ignore any counter examples. 

Mostly I think it has to do with whether gender and sex are different things. If they are then what defines a woman can be different from what defines a female as it is mostly social constructs. Personally my argument for this would be that practically speaking most times you make the call about who is a man or a woman it is not based on chromosomes or genitals because we don't have those on display. It's instead based on societal norms and secondary sexual characteristics that are more obvious to the casual observer. With that in mind, it is reasonable to separate those societal norms from the biological reality and define who is a woman based on those as it's the most useful definition. 

Reasonable minds can disagree on how a word should be defined, on the other hand we've got "Trump won 2020", "Vaccines give you autism", and "Jan 6th was antifa" which are not by any means the same kind of disagreements. 

Either way, that is not equivalent to making factually incorrect statements like climate change isn’t real or isn’t mainly caused by human activity, or Donald Trump won the 2020 election, or vaccines don’t work, or the January 6th rioters were ANTIFA. That’s detached from empirical reality.

Then gay people might not really be gay either then, since some people dont base what it is to be gay on how you feel or who you sleep with? Yet that I guess you would wholeheartedly disagree with. Just because some people believe something, doesnt make it a fact. 

Those are indeed false, but conspiracy theories are not the sole domain of the right, they occur on the left as well, such as "Trump rigged the 2016/2024 elections" or "the right are preparing for a genocide of minorities, detention facilities are extermination camps".

What fact do you think we're disagreeing on?

You do base what gender a person is by their chromosomes or their genitals. If you dont know, then you are just guessing. Just because a man has long hair and looks like a woman to you on the street, doesnt change or contribute to the fact that he is a man.

Well see now you're disagreeing with the dictionary. Does that mean that you are factually incorrect or instead that you disagree with what the currently accepted definitions are and their utility?

Just because some dictionaries state that does not mean its the widely accepted truth. 

Something being a widely accepted truth doesn't necessitate it being a fact. Personally I tend to go with the consensus of experts that study these topics their entire lives rather than crowd sourcing. Likely goes with my profession, but I value expertise highly in fields which I am not well versed.