Headline is inaccurate.
Transgender athletes are not barred from women's events. Female athletes who identify as men, or otherwise do not identify as women, can still compete in this category, as they have been doing already.
What the IOC's new policy actually does is make male athletes ineligible for competition in the female category, with very few exceptions. These exceptions are for athletes who are technically male but have a disorder of sex development that confers no male advantage, e.g. CAIS.
Transgender women aren’t ’male athletes’
Why not? Aren't you mixing gender and sex?
If you try to define athletic divisions by sex, you're going to have a hard time. The world's best athletes probably all have some unusual biology. About 1.7% of people are not completely biological male or female. I would expect that proportion to be higher for Olympic athletes. Excluding 1.7% or 2% or 10% of the world's best athletes from competing would not be fair.
Why do you believe that?