Maybe it's because we DO. And it's not just anal sex - I find the thought of a man touching another man in ANY sexual way physically sickening, as do most normal blokes.
That really wasn't my point, 16 Blades, which is why I bothered to mention that, as a normal homosexual, I find aspects of heterosexual sex pretty toe-curling. The point is, it is taken as read that, if you are heterosexual, you ain't gonna like homosexual sex. So why harp on about it?