Why is it that girls will allow each other to feel left out, but guys step up to the plate?

I was with my friend and some girls I don't usually talk to. My friend and the girls just let me stand there awkwardly and leave me out of the convo...after awhile one of the girls bfs directed a question to me but my friend interrupted me before I could say anything. Later on I was with a different group of people and the same thing happened a girls bf teased me after nocitcing I was just standing there cuz the girls were ignoring me. Why are were the girls being so ignorant!?!?