What if someone told you that your friend was...

Depends on the person.

If they said that about this certain friend called V I'd say "I totally agree."

If they said that about my crush I'd punch them in the face.

I don't think I'd dump a friend over what some random person says. They'd have to hurt me personally first.

 

Depends on who's giving me the information. There are a lot of people I know irl that would say things like this, but I always take their words with a grain of salt because their opinions aren't worth my time.

Now if this was coming from someone I like and respect (not just their opinion, but respect as a person) then Id be on high alert. I wouldn't flat out stop being friends with said person, but id just be really careful around them.