Here in Smogon, we have two different people.
On one side, there are the people where losing is a big deal to them. These people try to minimize luck as much as possible, as they need to win as many games as possible, and they don't want something that's out of their control decide their game fate.
On the other side, there are the people where they don't care whether they win or lose, as long as they play well and have fun playing. Like the others, they try their utmost to win, but, in the end, if they lose due to being unlucky, it's no big deal.
Personally, I used to be among the first group. But when I started losing due to bad luck, I decided that I cannot remain among them, so I left that group and joined the second one. I've also seen first-hand what happens to people who stubbornly refuse to acknowledge that you cannot win every game even if you're the best player. This is not a criticism to jrrrrrrr, but his initial outburst was just because, according to him, he was the unluckiest Pokemon player ever... and look what happened to him.
Pokemon is a game like Poker, where skill tells in the long run, and not in a single game. That is why I would ban OHKO moves and possibly also evasion in single-elimination Pokemon tournaments. But actually, I would actually ban single-elimination Pokemon tournaments in the first place. Since skill tells in the long run, the tournaments that make sense in Pokemon are Swiss system ones. And, as I said in the OU list thread, I would treat the ladder as a continuous tournament, where the player on top is not that who wins all games, but the most consistent one. (Unfortunately, right now it isn't like that.)
So I'd reiterate that I'd allow OHKO moves in Pokemon, but, to do so, we'll first need to change our mentality that a single Pokemon game is make-or-break, since that is horribly untrue.