So, while I think that someone could arrive rationally at a different conclusion than other regarding certain aspects of moral theology, and I don't think someone who believe in the liceity of dancing should be characterized as "lukewarm", one can certainly sense that the one poster is not being objective or rational, but has some vested interest in the outcome ... perhaps has her children enrolled in ballet, or something? She should be cautioned to do some self-reflection to determine whether she's being completely objective. There's another aspect that sometimes factors in from women, where they don't fully understand the effect that certain types of female immodesty might have on men, and simply because they themselves might not have the same reaction to the same types of things when done by men ... they write it off as hyperbole from some "oversensitive" types, often implying that they're perverts or something.
I'm also not huge on taking anecdotal hearsay evidence regarding saints ... without independent corroboration, since, just like with Padre Pio, you can find many fabricated "St. John Vianney" stories.
I base my assessment almost entirely on the guidance issued by the Holy Office under Pope Pius XI. That's the last Magisterial / Papal direction we've received on the matter, and nothing that the Conciliar Modernist Papal Claimant would say on the subject can be regarded as the least bit credible.
https://mikechurch.com/wp-content/uploads/2018/08/Modesty_Pius_XI.pdfI hold that the prohibition of ballet (as we've drifted from the subject of this thread) would fall under the same stipulation as "public athletic events", the idea being the same, that they're public. Presumably if the events are not public and don't entail mixed company (with men around), they may be considered acceptable for other prudent purposes. Let's say there's a ballet school, and the intent is for the girls to learn some coordination, grace, agility, etc. ... similar to gymnastics, presumably if these take place in a non-public setting and not with mixed company (with males interacting with the females), it might be considered acceptable. I just don't know if situations like that exist. I think that some events are only quasi-public, such as if girls might be involved in sports ... as no one is forcing any men to be present for these. In other words, just because men / males CAN show up, does that make it public per se? If it's an occasion of sin for those men, then why are they showing up there? But, let's say it's at school, where the student body (including boys or young men) are brought in to watch, that might be different.