By making pools appear smaller they encourage independent miners to (continue to) send hash rate there. Thus the evil pool operator doesn't need buy the hash rate himself, he's tricking miners into letting him use it.
True. I suppose creating a fake pool for a long con is equivalent to creating a fake exchange to gather POS coins with which to vote... With the exception that the fake pool will be at capacity for the attack, whereas the exchange voting with stake is much harder to detect, and is passive.
Agree, and not just a single fake exchange either. There could be all manner of corrupt platforms and investment schemes that exist, at least in part, to collect stake. In fact the market forces kind of dictate this, since such platforms and vehicles can likely pay a higher yields than honest ones. Furthermore they are paying those yields in units where they, alone, with privileged knowledge of their future plans, have good visibility as to underlying value. Not really so different from the fiat banking system in a lot of ways.