I don't feel weird when I play Madden, or a Batman game. If I thought twice about emotionally investing in a male character, I'd miss a lot of good fiction.

I'm not sure I care who's playing what female or male. I THINK someone I've RPed with for years is male, they've played a female, but it's never come up over years and I honestly don't care. It's IC. This is my level of care: after literal years, I still don't care if it's a guy or girl. 

Whatever, man. 

Romance, even, I don't know that I care. It's IC, and I'm not really looking for attachment outside of that, so why would it matter?

I wonder if you can't just chalk the look you got up to toxic male masculinity and move on. I'm sure there are people here who'd probably lean closer to your friend's response, but probably not worth the potential conflict for them to comment. There will always be those people.