If Steem Power acted just like a multiplier for rewards of your own posts, that would be a reason to stay big & strong (and to became big, you'll have to be active member). I would have nothing against this.
If Steem Power is just a way to create an oligarchy (whales) from a decentralized platform, it makes no sense to me. A user with more SP is not smarter or better at judging content than other users, and vice versa.
If you really like how Steem works (rules) you really can't complain with whales behavior.