I personally don’t feel my masculinity is threatened by my carrying around a hot coral “pink” card, and I use it with a sense of pride. I also like seeing others use it, and immediately feel a sense of kinship.
If anything, I wish there were only one card colour - since I agree with some posters on other threads that the introduction of multiple colours as part of Monzo Plus risks diluting the tribal sense of belonging and community many Monzo customers feel.