CMV: The phrase "man up" is used incorrectly and it's a microaggression against men

I used to think the phrase was a common way to say "stop acting like a bitch and tough it out" and it was used more in the context of sports. But now, it seems that men are saying it more in a derogatory way like it's a derogatory slur. When I say "man up" it's in a literal sense meaning that you are being too much of a bitch so I'm trying to help you toughen up. I'm not trying to belittle you or put you down.