The Steemit guys talk about collusion and giving those with most votes a disproportionate amount of rewards as if it's a good thing, but they don't really explain why.

In what way does it help Steemit that 99% of its users get close to nothing but 1% get the vast majority of rewards?

It also creates some kind of perverse incentive, which makes quadratic voting even worse than FPTP voting, if it were to be used for politics. Think about it - with FPTP you're already incentivized to only vote for the two biggest parties/two most popular candidates, due to the spoiler effect.

With quadratic voting you're super-incentivized to vote for the two most popular candidates/parties. Can you see how bad quadratic voting would be for a democracy, by creating a permanent super-duopoly? If so, then you draw the same conclusions for why quadratic voting is bad for Steemit.