why not, I see it as some kind of liquid voting that you can program :)
there is a nice post about the benefits and cons of using bots in steemid. Lets see if i can find it again.
I think more fair it would be to make it more easy to automate the voting also for normal not so tech skilled people, so that steemit can evolve to a liquid democracy where you can delegate your votes.
A downvote bot can for example look for bad spammy content with bad words.
UPDATE:
Here the link to a post about wang:
¨Remember, the bots can be a force for good and bad within Steemit. You'll have to judge each on it's merits :)¨
https://steemit.com/steememe/@benjojo/in-honour-of-wang-one-of-steemit-s-most-beloved-if-somewhat-contentious-bots