I told off my bf’s friend because he was talking to someone underage and now they’re all mad at me... was i wrong?

This happened a while back, but it’s always bothered me.

A while back, my boyfriend and I were in a call with two of his other friends. One of the friends has a habit of saying rude, discriminatory, and sexist things about people of color and women. During this call, this guy adds a girl. I. Freak. Out. Not because she’s a girl, but because she sounded waaaay too young to be talking to people our age (we’re 19-21). I ask her age and she refuses to say, and he follows with “it doesn’t matter we just play games”. I ask more questions, such as were they met, and he says Snapchat. I freak out even more. Why? Because this guy has a reputation of sexing girls on SC, gaslighting them, and blocking once he gets what he wanted. I let the girl know all of this and she stayed silent. I continued to tell her he’s a creep and she really shouldn’t be adding random people, especially on SnapChat of all places. He asks “why?” at this point and i tell him it’s so obvious what Snapchat is primarily used for and he says “we’ll you’re old and people don’t use SC like that anymore”. I called bullshit and reminded him of his history with Snapchat and girls, and he brushed it off... anyhow, eventually the other friend hops in and tries to defend the guy and they both start calling me jealous, crazy, insane, etc. My boyfriend felt uncomfortable and mostly didn’t say anything the whole time, but mostly sis defend my position. Anyhow, we hop out of that call and into our own.

My question is, was I wrong for getting upset about his friend for talking to an underage girl supposedly only for gaming reasons?