Of course it's wrong. And it's spouted by people who have never worn one (or been to a gym).
I wouldn't say it's dangerous, particularly, on this thread, though. Because obviously everyone is showing it up for the really stupidly tedious tactic it is.
Sports bras are designed to help women and girls compete in sport. Hence 'sports' bra.
They're incredibly common, because you wear them for tennis, aerobics, gym work outs, the lot.
Binders come with a warning to specifically refrain from sport if you are wearing one, as it restricts your breathing and is therefore dangerous.
I know you know that Beowulfa 😁
I'm just enjoying pointing it out again.
As I never tire of saying, one of the biggest drivers of people becoming gender critical, is what TRAs say.