"Hey dude, I like totally don't agree with how you just shot that 15 year old girl through the left eye because she wouldn't kiss you. But I couldn't do that, so I respect you for it." *
There are plenty of things other people can do that I can't, or won't, or have never even thought of. Just because some guy can do something I can't doesn't mean I should just dole out some respect to him by default. Respect (in the usage you bought up) is something earned, not something you should just get for being you. If you're good at what you do, people will respect you for it.
Basic respect, however, (ie. Common courtesy, not being a prick to someone for no reason etc.) is something you should have for everyone. Unless they do something that warrents it being revoked.
* No, Blink 182 never shot teenage girls. I'm not saying that.