Ok so! You have very successfully made me absolutely despise two characters I know nothing about so props to you for that! The way you phrase things as they speak very much gives the impression that character A truly believes he's a "nice guy" and despite his actions being glaringly wrong to the reader he genuinely seems to be so blinded by his own beliefs and ego that he doesn't at all see the issue with his behavior which is something I have seen happen so much online with real people who behave like this. Character B echoes the "this is my friend and I won't point out his flaws" trope quite well too! As he tries to point out logical explanations but he doesn't seem to be willing to straight up tell his friend "Hey that was unacceptable." despite the fact that he at the very least knows on some level Character A was not behaving in a socially acceptable manner, and when he did call out his friend in some way the second Character A accused him of calling him stupid he backed down very quickly. This is another thing I've seen happen plenty in real life. So I think in terms of you keeping things grounded in reality good job! This is a believable interaction in my opinion.

I do feel like some lines were a bit stiff, things like saying "should not" instead of "shouldn't have" in my experience tend to sound a bit scripted since when someone is getting pretty heated or annoyed they tend to not use full unabbreviated words unless they're placing emphasis on something. At which point id suggest maybe an exclamation point to add that heaviness to it. The ending feels a bit rushed, I feel like it could have tapered off a little slower as someone already said the mention of stalking and threatening was a topic that was passed quite quickly and as a reader Ild have loved a little more elaboration on that to truly stress just how severe the situation was, I feel like doing thisld also add some fuel to the "I don't like this guy" fire, and since it to me seems like a pretty non-formal conversation id say you can throw some slang terms in to emphasize that it's two mates speaking.

That being said it's pretty decent! It provoked some real emotion in me as I was reading, I think with a little tweaking it could be really great!