Definitely. You could also take LinkedIn as an example of a network with less negative behaviour, since people use it for specific purposes (I've used it to find potential contacts for stories, search for freelance writers, etc.). We all use Twitter to put out stories and share interesting discussions. And there are several very interesting and/or helpful groups on Facebook (plus, of course, it keeps you connected to people you might lose touch with otherwise). And personally, with all the uses I have for these, I can't just up and quit them.
The advertising based "free" business model, though, is deeply problematic. Just as it is for, say, the news media. And when it comes to connecting people and sharing art and so on, social media right now is just great. When it comes to, say, politics, there is a systemic tendency to polarise users and amplify extreme positions. Not because anyone wants to do it, but because that ends up generating the most attention and revenue. Plus, the platforms track you all the time and serve up the data to advertisers, who are trying to manipulate your behaviour—which is fine, I guess, if it's Nike trying to sell you shoes, but the obvious negative example that comes to mind is again politics (US elections, Russia, the way political parties may be taking to it in India, the way the Chinese government monitors WeChat).
The argument for quitting is the quintessential "vote with your wallet", telling companies that you don't like their service and, hopefully, pushing them to innovate. Again, this is just one argument, and even those making it, don't expect everyone to quit all social media—for many (including me), it's just not feasible. But I'd say it's still a worthwhile idea to push companies to explore alternative business models (like how WhatsApp used to have a $1 per year subscription fee once upon a time). I'll admit, I'm not sure how exactly to do that (apart from quitting/cutting down social media time). Thoughts?