I meant that in a legal sense. As per the definition below, a human is any extant member of the genus homo, which would be determined by DNA, biology, anatomy, taxonomy etc.
http://dictionary.reference.com/browse/human-being
If you prove that another member of homo exists, it's human, and has all the rights of a human, yet this one is currently allowed to roam free, trespass, take live stock, potentially hurt people or kidnap. People wouldn't tolerate it from any human. You also can't just call it and treat it like an animal because it's human, and there would be litigious people who would consider it gross discrimination to not give them their rights.
So therein lies a problem, it's dangerous for us legally, and dangerous for them because we might choose to eliminate them if they can't behave or if they're ever proven to have taken women or children.
There are some humans who would love to be able to get away with what bigfoot gets away with, and we don't have two sets of rights for members of our genus.
This is just a gap in our categorization because we've never considered what to do with a population of wooley wildmen other than turn a blind eye to the whole thing. I'm not even going to touch what it would do to religious beliefs connected to human origin beliefs. So yeah, proving bigfoot is a member of homo would be a volatile endeavor.