I'm pretty sure its being drug down by Bitcoin's problems not just crap posts. Google doesn't just see Steemit as one big website. It can see that there is individual users. When you look at your address bar you can see that Steemit.com is highlighted and the rest is kind of grey or dull. Now I agree I have followed a couple people I regret following but unless they have some bored friends they will not be rewarded for their crap posts.