I've never raced Lemons, but I have raced with NASA, and I know lots of my friends that I've made in NASA have moved over to Lemons, so I'm following. When I first heard about Lemons, I thought it was hilarious and always wanted to make a car for it. I love racing (the competition, the speed, the build) and I also love watching Junkyard Megawars. Lemons combines the two into a weekend of pure joy. Why would I frown on it?
As for the difference in experience, of course they're different, but one isn't better than the other until you include money. In NASA sprint racing, you have less than 40 minutes to finish as high as you can, which makes for dicey passes and balls to the walls driving, but also times when you or the leaders have checked out and you're just grinding laps. In Lemons, you have 14 hours to accomplish your goals, so getting around the Lemons equivalent of a Wreck Pinata doesn't have to happen right now, just motor past him on the next straight. Lemons makes up for this "lack of excitement" in track time, strategy, the fact that there is nearly ALWAYS someone to race and the spectacle. When I walk around the paddock at a NASA event, I'm drooling over parts and getting ideas. When I'm virtually walking around a Lemons paddock (haven't been to an event yet), I'm laughing my ass off and getting ideas. Po-tay-to, po-tah-to.
Either way, I'll make friends wherever it is that I go. Sure, there are some jerks at NASA events, PSA events, SCCA, wherever, but I'm still going to be nice to them, and try to befriend them. Why? Maybe I'm a glutton for punishment, but I also know I really don't like it when someone doesn't like me. The OP was talking about what someone in a forum is doing, but things are generally different in person. Only on the Internet can an argument or "shouting match" happen over such a trivial topic. We're all racing, who cares?