Nothing wrong with the video. Nothing wrong with going to work out with some back-yard grapplers. The ATTITUDE is the problem.
First off, he openly mocks people who grapple for fun in their back yards without any formal training. And don't get me wrong, he is certainly not the only one. There is, however, nothing wrong with people who enjoy backyard grappling any more than people who enjoy backyard football, baseball, etc.
Things brings us back to a question concerning why you train BJJ? It's been established many times over that the majority of Sherdog posters do not train BJJ for self defense. This would suggest that they do it because it is a fun activity and/or for fitness. If that is the case, then what "bar" is Sean showing these guys? Are you suggesting it's more fun to train in a formal class than it is to grapple with friends in someones back yard? That's pretty fucking subjective. The only "bar" that Sean could have been showing these guys is one concerning the effectiveness of backyard grappling vs. formally trained grapplers. And since we've already established that a vast majority of forumites don't train BJJ for its "street effectiveness," it makes VERY little sense. Unless, of course, you're suggesting that the guys who posted the video were grappling in their backyard for self defense purposes rather than for fun... in which case you might have a point. You might also meet the DSM-IV criteria for having an intellectual disability, but you'd at least have a point.
It's no different than a semi-pro/pro football player showing up in your backyard to show you how ineffective backyard training is in preparing you to play pro ball. The only problem is that you play for fun and don't have any intentions of joining the NFL. Thus the guy is an idiot.
If some professional ball player wanted to show up at my house and play ball with me. That's cool as fuck. I'd be happy to have em. The moment that same ball player starts making fun of me to random people because my non-existent training is inferior to his own, however, he becomes a douchebag... and that's exactly what happened here, regardless of how you want to try and sugarcoat it.