Question No.1: Why do guys think it's okay to say mean things to girls?

Maybe I'm exaggerating saying that every guy is a douche towards girls but I have met my fair share of guys who are just completely mean. Okay so they probably don't fully understand how insecure some girls are but really, why can't they just be nice? Literally half the guys in my class are just freaking dick-heads. They just annoy girls, they just have no idea how painful it can be to some girls.

Confession Time:
A few years ago, I think I was in grade 6 there were these two guys who were just soo mean. One day they said to me that I have a uni-brow and hairy legs (which I think I did) so one day I took my big sisters tweezers and plucked my eyebrows and then I took her razor and shaved my legs. That's how insecure I was. I did that just because someone teased me about, and also I didn't even pluck my eyebrows right, I have thick, Cara Delevingne-like eyebrows and I plucked them so freaking thin I looked like Morticia Addams, luckily my thick and fabulous brows grew back.

Anyway I know that this situation happened a few years ago but I still know those two guys and they're still as mean as they were before, so to all the male population;