Affiliate Marketing Secrets

Sorry if this is a long read.
I met these girls in one of my classes when I helped them out with studying for a test, since they were freaking out. After that, they have started talking to me quite a bit. I did not mind because it was nice talking to cheerful people and I wanted to be respectful. I thought that they could use a guy friend to have casual conversations with, share a few laughs, or get help with issues.
However, my guy friends noticed this for some reason and approached me, asking why I would be “affiliated with ugly girls”. I did not approve of them talking about them behind their backs like that, but they just teased me even more. I did not understand this because they were really geeky guys that rarely talked to girls of any sort. This has been going on for a couple weeks now- they are still calling those girls ugly and harassing me for talking to them. I could care less if they teased me, but it crossed the line when they bad-mouthed those girls like that. I will admit that they were not the most attractive girls in the class, but I feel that they have no right to judge them like that. I think that every girl is beautiful in their own way. However, I have considered cutting off all contact with them to keep my friends from bothering me about it. I have not done it yet because I want to be more considerate to the girls.
I feel like cursing them tomorrow since they are getting on my nerves. What do you think I should do? Should I just ignore the girls now?