Well, I usually talk to all R8 owners I meet... except guys who drive white ones from Seattle.

Kidding, kidding! Perhaps the fact that he chose to drive a Gen-2 over a Gen-1 was a warning, though?

OK, I kid AGAIN... please accept my apologies, Gen-2 brethren!
But in all seriousness, I've only ever approached (unsolicited) ONE other fellow R8 owner. I was in a quaint little CT town (as we have many here), and a Daytona R8 pulled up literally where I was walking. Out jumps a young dude and his girlfriend. I immediately complimented him on the car. He came over, and I explained I was also a fellow owner. We got into what was probably a good 10 minute chat while his girlfriend started to befriend my wife and son. He was a very friendly guy - even chatted about R8Talk quickly.
So, while I don't have a lot of data points, my one experience has been a positive one. On the flip side, I know that I'VE personally entertained every single person who's ever cared to approach me. True, none of them were R8 owners (that I know, at least), but nonetheless I'm polite and personable with everyone. The way I see it, I don't care what it is someone is talking to you about - your car or your socks - if another human being is trying to interact with you, you treat them as you'd want to be treated. Unfortunately, I don't think everyone thinks the same way. And for better or worse (in this case, probably worse) people with money are the ones who can afford to buy flashy things... and when they treat people poorly, the "flashy thing" becomes a symbol of that poor character. And that may be part of the reason that I'd go FURTHER out of my way to come across as a decent human being (which I hope I am!) if someone specifically approaches me about the R8. That last thing I want to do, as a car enthusiast and someone who knows how great true car-people are, is feed a stereotype about exotic owners.
But at the end of the day, I wouldn't take it personally. It's impossible to know what was going on there. For all you know, he was in the middle of reading an e-mail from his wife asking him for a divorce. I'd give it the benefit of the doubt. For what it's worth, there's a forum here full of R8 owners, and I've got to say - there are some really awesome people here... to the extent that I'm pretty sure I'd enjoy talking to the majority of people here about much more than just the R8, as we just have so many interesting people - intelligent, all sorts of walks of life, generous with their time and advice, etc.