I don't think there is some policy here now, especially when Steemit is on its early stage and steem power is badly distributed among ordinary members. And your issue is not an exception - I saw how some whale double downvoted some good man just for mentioning synereo and putting link to this site and it was not advertisement just some thoughts about competition. So for the present moment rich people's opinion is worth more then number of supporters. I guess this situation will change in future but now things are what they are. By the way, you can check who downvoted you with help of steemdb.com and send this guy a message. We are all humans and can do mistakes. Maybe that guy will change his mind after your message?