Stoicism doesn't equate to being impossible to interact with. Besides, straight men are important for comedy. He still totally talks to people because talking is important for normal humans to, y'know, function in society. I never said he'd be difficult to talk with, let alone avoid chatting altogether.

And take Guts, for example. He's one of the most serial characters in manga, and he's got a large and growing group of friends to talk to and who support each other.