I don't think it's so much that Dante thinks very highly of humans in general - Kat in particular, sure, but he's pretty much indifferent to the rest of us. But the one thing Dante's fought for all his life is the freedom to live as he chooses. So it's not that he believes humans are inherently good and won't turn the planet into a hellhole as much as the demons ever did, only that we have the right to make own own choices, even if they're disastrous ones.
It makes his position the extreme opposite of Vergil's, true anarchy, and just as dangerous for it. I mean, what's Dante going to do, go find a new trailer to chillax in while people start burning everything down?