My curation criteria is here: https://steemit.com/dana-edwards/@dana-edwards/my-criteria-for-curating-posts-on-steemit
I don't downvote just because I disagree with the content. I do not downvote if the content makes obscene amounts of money. I let the market decide the value of every post and I respect the decisions of the market.
If a post is abusive, or if it violates human rights for example, then I'll downvote. Don't threaten to harm others or initiate clear abuse or violence and I more than likely will not downvote the post even if I don't understand why other people value it so much.