Just a reminder - most of the running fans don't give a crap, what a pro runner thinks about each of them. On the other hand a pro runner should be very careful, what he/she expresses publicly about his/her fans. They live through social platforms and are existentially dependent on them. The thing is - he/she is there for the fans. If it weren't for the fans, the pro runner would have no job (sponsorship). Nobody, except for her close family, cares about the opinion of Molly H. - a soon-to-be-mother, but a lot of fans might be interested about opinion of MollyH - the runner. Unfair? Well, such is life. Thus any public persona that thrives on the fan base - be it an actor, politician, famous athlete, etc. - should prepare for a lot of crap. Public figures have to endure public scrutiny and criticism - whether justified, or not (slander excluded). And that includes any - oh-so-offensive remarks about their bodies. After all, the body is what pays their checks, and what fans are perceiving 99% of the time. If they are not cut for that, they should choose another vocation, where nobody would care about their appearance, body, their gender, or performance of their physical shell. Easy as that. And it does not matter whether they are males, females, or any other gender they identify with.
You can't have it both ways - be a pro athlete, be adored by the fans for amazing feats you can do with your body, and at the same time, be sheltered from any speak about your body - positive or negative. Just because you happen to be (or identify as) a woman.