Crazy Man DownVoting - Why?

so it's not the first time I found someone's downvoting like crazy, but always.
I don't know why, I tried making a research about that I didn't found any reason for that.
it looks like auto-voter bot that downvoting 10% new posts,
here is a picture from steemd

https://steemd.com/@camillesteemer

if you guys can give me any information about why this guy and other people doing that type of stuff, it'll be cool.
he got my attention cause I saw 2 posts of mine get 10% downvote, but then I saw this...