I’m sorry that’s your response to a post pointing out the HUGE differences in beauty culture/cultural narratives about men and women’s bodies and that sexism exists.
Of course men are allowed to post about and engage in body positivity (something I’ve said again and again on this blog). The issue is when people- like some of the commentators on that post- pretend that men and women’s bodies are talked about in the same way or that men experience equal expectations and narratives about their bodies to what women experience. That’s simply not true, and erases the existence of sexism.
Men can and should practice body positivity. They just need to acknowledge male privilege and sexism- which is really all that post was doing- while they do it (because men should do that always).