EE, the weights and lengths are different. Many are under consideration for change. Many in athletics aren't convinced that the discus weight for women actually challenges them, and think the hurdle heights are shorter than they need to be, giving an advantage to shorter women that they should not have. These debates are around stereotypes of what women should be physically capable of, and what the 'ideal' strength and size of a woman is.
If you don't think that women's activities are lesser, why put as a problem that women 'prance' to music in gymnastics rather than the problem being that men do not.
I find it difficult to take that you are criticising an arts based activity like ballet in comparison to karate - partly a combat sport. There has to be some critique there to be made of violence, and the normalisation of it.
It isn't just that the issue of stereotypically male things being seen as better, it's that the stereotypically male things can have harmful social messages within it. Masculinity doesn't appear from nowhere - it's taught to boys (and now with supposed gender neutrality, increasingly to girls).
So while in the real world I'm sure I don't care too much that your kids did karate and mine did dance, theatre etc, because different families do different stuff and such is life, these decisions are in part about values and about attitudes to gendered activities.