I think in many cases Simons' ire is misplaced... it's not necessarily that poor tone-deaf fools' fault he's up on stage trying and failing to sing... it's all the people that told him he can; all the people that said "Wow, you sing really well, you could go pro" instead of being straightforward and honest and telling them "No, I'm sorry, you really shouldn't be singing anywhere other than in the shower. You just don't have what it takes."
And with some people, you HAVE to be somewhat harsh because they'll (and their supporters) continue to delude themselves, justifying it with "Well, everyone has a few setbacks... I'll do better next time." I see this a lot on web-art sites like deviantart and elfwood... someone draws some lame-ass anime/manga-lookin' furry thing that's been done 5 billion times before, usually far better, and everyone supports them, saying 'Wow, I wish I could draw that well, you're really talented."
No. They're not. They're derivative and lame, and if they'd spent as much time actually learning to draw as they do sucking up unwarranted praise, THEN we might have something worth talking about.