Furries are like any other section of nerd culture; just regular people who have a passion for something. Some of them are into some less savory stuff, but a lot of them aren't.
The thing that makes the furry fandom different from almost every other fandom is that their focus is not on one specific show, movie, book series, etc. Instead, they're fans of a wider concept, that concept being anthropomorphism. Because the fandom's focus is so general, you can't really place all furries into one group, at least not the way you can with bronies. "Furry" has become a sort of umbrella term for a wider range of interests.
This is part of why you can't say that bronies and furries are the same thing. The only attributes they share are those belonging to all fandoms, and the fact that that their focus involves some sort of animal. The similarities between the two are superficial, and at their core they are very distinct and different groups. Is there overlap? Yes, but that's because there's overlap between all fandoms, and not because they have any significant relationship beyond that.