This division is arbitrary. The reason for this is the premise of fair competition that identical people should compete. Yet white males dominate male swimming whereas black males dominate male sprinting. There have been physiological explanations. Knowing that, why don't we split the competitions accordingly? It's easy to see that the whole premise of fair competition is very naïve: where do you stop? What are the criteria for determining if competitors are "identical enough"? Choosing these criteria will be a political choice. Transgender people in sports are disturbing the status quo, but they just made apparent the inherent instability of the thing.
Now i don't know about you, but when i personally do sports, for one i'm not good enough that physiological characteristics make the greatest differences: this problem mostly appears when we reach the limits, by "optimal training". Second, i'm usually playing for entertainment which means that i will mostly play to be part of a good game, show off and see nice skill displays, and share this experience with other people, some of them with different levels of training and physical capabilities.
I just wanted to say that this thread is imho unrelated to the issue of transgender and more to the fact that competitive sports is broken and the political struggle between professional and amateur sport.
what the hell, how is Men's and Women's sports categorization arbitrary? its clearly defined who plays in which category.
No, actually the reason is that it makes both watching and competing more interesting. A competition where women never got anywhere near first place would mean women would simply stop showing up (or vice versa). A boxing championship with no weight classes would mean no lightweight boxers would sign up.
On the other hand, with enough subcategories you can get to the point where some competitors win by default, or where you have championships of one or two matches.
So no, it's not arbitrary to separate competitors by some physical characteristics and not others. There are practical reasons to do so that are unrelated to the whims of organizers.
If we remove the gender division from, say, javelin throwing (random choice; current difference in world records there is currently 30% for reference). Now there won't be any (cis) women competing at the top level any more.
So somebody goes ahead and creates a women's division (or whatever you want to call it). Should we somehow forbid this? Or would it be required that they accept any transgender individual in any state of transition? And either case is just "back to square 1" - no cis women have a chance. I don't see how "let's remove the 'women' category in this competition in the interest of fairness to trans people" is improving things for anyone...
I know I'm not the first person ever one to bring this up, but it's unclear to me how letting someone with (largely) the physique of a man compete against women is acceptable.
There's a reason why (competitive) sports are usually divided by male/female, and that reason still overall holds for someone who is trans. There's a lot of gray area here depending on if and when they undertook HRT, sure, but labelling this as "intolerance" is not right in my book.