And this is reason to let furries have a board why? Just because one shady thing is inherently around from 4chan's core subject/reason for existence, does that mean we have to let every type of crazy/creepy under the sun into 4chan with welcome arms? Fuck no. This is why there isn't a drugs board, or loli board etc.
Also society at large doesn't even know what furry is because it is just that heinous that people don't even speak of it. Everyone knows what pedos are however and so they can instantly assume things about lolicons. The internet-aware people that do know of furries though (that is, us), fucking hate them so much, which is an indicator that if even the weird internet-people don't like furries, then why would normal society treat them any differently? Look at how much backlash there's been over bronies due to the clopping nonsense. Wanting to fuck an animal may be less offensive than wanting to fuck a kid, however, that does not mean that society will accept such people freely talking about their bestial habits and desires within earshot. Same principle applies to 4chan, and a furry board would turn a distant (and literally never welcome) group into neighbors with other boards overnight.