Just my $.02...

I think the big complaint from most people is more a matter of variance than whether a super-loose game can be beat. As all of the previously mentioned stats suggest, it seems like you will get sucked out on A LOT and have plenty of losing sessions, but you win big when you hit. Some people don't like the natural variance from SSHE, and their play seems to be negatively affected by these expected swings.

I think that another reason why these games are reviled is that optimal play seems to be rather mechanical. I'm not sure about that, but if it's true, I could see how "poker player" would not find these games appealing.

I agree most of the complaints stem from the variance. But I really haven't had that many losing sessions. As long as I'm 4-tabling, one or two of my tables make up for my terrible variance at the other ones. That's the thing about these extremely loose games... you can lose six big pots in a row, but then win one or two and be right back at break-even or sometimes ahead for the session.

I really don't think these extremely loose games are any more mechanical than tighter games. In both cases, you're trying to figure out what kinds of hands your opponent has to determine the optimal play. I know with extremely loose games this comes in handy when you're value-betting middle pair on the turn and river (see my Playing Too Tight part-2 post for those examples).

Nonetheless, I agree tighter games require more deliberation.