I'm a living example that not all furries are gay, as are my friends Troi and Chad. I'm straight without a doubt and so are they. So your buddy can call his argument more than a lost cause. =P
As for Gay rights, I just think sexuality should be someone's personal business and nobody else's beyond the attraction or lack thereof. It should only be brought up when appropriate, not celebrated, nor degraded. It should just be. Everyone has a right to happiness, and something so benign as what people you feel attraction to or not should not be a deciding factor on how anybody, including political or legal bodies, might treat you.
That being said, of course I believe that people of differing sexual orientations and the like should have fair and equal rights and treatment. It's just a different feeling. Like how I don't like pink and yellow, does that make me anything less? No. I just don't feel the same way about pink and yellow as someone else does, but I love blue so goddamn much.
Also, there is such a thing as being legitimately unsettled by homosexuals but not actually against them. And It is called homophobia, but the term has just been used differently as of late for the sake of simplicity, since it's such a rampant problem and it does seem like some of those people are scared of harmless things. Just so people don't get the wrong idea of Silver down there.