While I do agree that it isn't the most sophisticated and mature place to be on this site; it in no way reflects the amount of knowledge on this site. Our appeal to new users reflects more upon the knowledge presented in our Q/A (the actual site content).
If anything, the problem lies where it always has for this site with the ridicule of the users that post "PLZ HALP MAI SRVRZ ON FYRE LULZ" questions or easily googleable (that really needs to be a word now) questions.
While we do seem to have developed a bit of a chat 'clique', more often than not, when a newbie pops into chat we take our time with them either pointing them to ask their question on the site, or provide some type of help to what they are asking (obviously depending upon what they're asking whether it be advice on a question or whether a question is OT or not, etc).
I have also seen plenty of times I'll pop into chat and see serious technical discussion going on or mild debate over what vendor/product is better (all friendly as in no one taking cheap shots on a person debating)
The chat simply is that, chat. People coming into a common forum to either blow some steam, crack some jokes, and try to have something brighten their day if it is crappy/boring. Maybe some toning down is necessary, but I don't think we need to moderate it all to hell and then drive away the humor of the chat.
IF ANYTHING...
..should need to be done, maybe make a new chat room that is, essentially, labeled NSFW or SFBS Room to let people know what they are getting into and which chat is the place to go for some genuine help. With the way SE's chat works, it is not a big deal for people to be in multiple rooms so, I for one, would not care so much about having a SF chat for serious discussions and one where I can post ponies and memes and have a good laugh, if it has to come to that.
tl dr; Chat is fine, and maybe needs to have a new BS chat room, in addition to Comms.