I'm not sure why Jonny came up with such a bold conclusion about this topic lol.
To answer your question, a lot of guys bust each others chops and shit talk just out of humor. At work we do it all the time because it's just funny to get someone worked up, though they know it isn't serious.
Not all guys do, but the guys who do, do it because they're insecure in their manhood... They think that liking someone or showing emotion isn't a manly thing so they try to hide it around their friends by being dicks. On the flip side, some guys are just dicks to begin with... they're actually just pretending around others to get them to like them.
That's how those guys relate to each other. A lot of guys act every sarcastic and macho to each other. They realize that kind of communication won't work with you do they act more civilized and sympathetic.