They can already do that with a 51% attack anyway. Maybe I'm being naive, but I agree that I can't see the mining community letting such an attack happen.
It's also realistic to say that if an attacking entity started a selfish pool, there would be a percentage of the population that would join that selfish pool.
It's obviously the wrong move, but just because you're a sociopath doesn't mean you're smart.
I hear people say to me all the time that it's "ok if I'm the only one doing it". If this papers strategy is effective, it is a realistic threat that lowers the bar necessary to destabilize the network. 33% to take over the network, but much less to start the ball rolling.