There's a lot of fake news, exaggerated statistics etc. in posts that reach the front page, since most votes are based on the title or a skim of the content. That's a problem that exists on most forums, and the "solution" most sites end up finding is heavy moderation, but I think this is a lazy and uncreative answer. A few things:
It's unreasonable to expect everyone who votes to fact check everything, or even read the entire article if it's long.
There are idiots (and trolls) on this site who think spreading fake shit is good and that fact checking is for fags (if this is you, I'm sorry to inform you that you're retarded).
When you do fact check something, a downvote doesn't do much. Pointing it out in the comments has mixed results. If there were a way to indicate that a story or whatever may be bs, that could signal to others that the source might be worth looking into and go a long way to curb trolling and spamming. Having it restricted to a minimum CCP (nothing crazy, just enough to stop those who aren't members of the community) would prevent abuse.