You have to understand the history of this site. CS50.SE was not created through the usual process of definition, commitment and private beta; pro tem moderators were never appointed from the ranks of active, helpful users. Instead, this site is moderated by faculty and staff of the course itself (and one faculty member who is not listed on that page).
Jaydles gives a good summary of why in this answer:
This is an experimental partnership with edX.
They're essentially testing out how our engine might work as a
replacement for their class forums. They educate people. Online. For
free. We like that, so we're willing to see if we can help or not.
While a lot of their needs fit pretty well (specific questions about
course concepts, etc.) some of what they're doing isn't a natural
match for our model (gtky, back-and-forth discussion, etc.). But we
thought it was worth seeing how it would work if we gave them the
tools and let them try them out.
Based on the above, it's not clear whether these sites were ever going to be launched as part of the existing SE network. As such, judging their content based strictly on the standards of that network is questionable.
Now, I'm not unsympathetic to your points. Looking at CS50.SE in the context of the network, we're definitely having a hard time finding our footing. I'm fairly active on the metas of sites that I frequent; I've tried to engage this community in the same way with limited success. Seems that most users who come in with some experience on the larger network don't stay for long. We struggle sometimes to drum up enough votes to close questions. Not many opinions are being expressed here on meta.
All that having been said, these folks also have a subreddit and a facebook group to maintain. Those are much less experimental formats and arguably deserve the bulk of their attention. When you're doing an experiment, sometimes you learn the most by sitting back and letting it run its course; if we treated this site like just another SE network site, we'd be trying to fit it into a mold that we already know isn't ideal for an online learning companion site. It would be counter-productive.
I don't know what is in the cards for this site. CS50, the in-person, for-credit version at Harvard, has just wrapped up another semester, and the 2015 "season" of the edX MOOC is about to begin. I expect a very large spike in activity starting around a week from now, and hopefully staff will have a little more free time to give some attention to this experiment in the coming months. I'd like to know their impressions and I'm hoping they've given a little thought to the challenges we've encountered (code dumps! code dumps everywhere!) and perhaps even been collecting some more sexy data for the blog. Stay tuned...