Its because a man who is well into adulthood and is still a virgin, despite actively trying to date is at the very least a yellow flag for virtually every single women on the planet. That's why. "I want no man who no other women wants". Every man has an awareness of this and every man at least subconsciously dreads it, which is why its considered a "lame" and shameful thing. Sure, nothing wrong with being a virgin... but staying a virgin? As an adult? Despite being totally attracted to women all your life? In that case, something must be off, right? The dating advice a man like this is given is to change. Cause the way he is, he doesn't deserve to be in a relationship anyway. Obviously. Its self-evident. A virgin man who fails to get any results despite trying desperately needs to change (and probably go to therapy asap). It goes without saying, right, ladies?

There you have it, the term "virgin" for men is tainted by this eventual yellow flag status which is fundamentally real due to how women work. No amount of "you can do it, king!" will make this underlying truth of "you are surely not good enough the way you are" NOT scary for men. And if it is, then men (and women) will use virgin as an insult. I honestly think the only way virgin shaming of men will go away if people literally stop being mean to each other, period. In other words its here to stay. And btw I also think this is a big contributor to toxic masculinity, which is just guys trying desperately to avoid this fate by acting like a big deal/tough guy/real man.

All of this doesn't really apply to women like at all for the obvious reason that losing your virginity as a woman is easy as fuck. Men are generally down to have sex.