there are clearly men who pretend to be trans to get off on something and there are clearly trans people who are nothing like that at all.
Yes, and that quote wasn't inferring anything about "to get off" (although the rest of the article did). It was directly addressing anyone, including your "nothing like that".
Why do their "therapeutic needs" outweigh everyone else's?
The reason those who might "get off" can enter is because they're piggy-backing on some leeway initially given to your favoured trans's "therapeutic needs".
So there's an initial direct violation by your "nothing like that"'s, which for a while was tolerable, but now the consequences of that violation have got way out of hand, with loads of "definitely like that"s taking advantage too, on top of an increased sense of entitlement from everyone involved, and we can see why it was a mistake to let that initial violation slide.