Well, that's the tricky part. I have been downvoted, fortunatelly by very small accounts and I haven't figured out yet why. I have been posting lately on the Inktober contest. All my drawings are original, I do not buy votes, etc. The only reason I can think of is that the person downvoting is an artist and I am not. And my drawings insult their artistic sensibility. If the downvote will come down to a matter of taste (whether we like a post or not, or whether we feel offended by someone's ideas), this is gonna get very messy.
Steemit is being propagated under the premise that there is real freedom of expression here; that this is decentralized, etc. And yet, I have seen big accounts downvoting users because of some argument, because of association, and the whole list of reasons why a post can be downvoted can get very long. I think that can be very dangerous for the platform.