Post again so i can get flagged again by denver and bernie? OK sure... whatever I guess there's nothing wrong with putting myself in the dunking booth.
The "rules" depend on who you ask (or at least the answer you get about the rules depends on who you ask). Some people (like @berniesanders says in the comment above) say there are no rules. Its a free and open blockchain. Personally, i find that model more appealing, though most here do not acknowledge it. If thats the case, then I cast my downvote on the free and open blockchain, as i'm free to do, because i think porn appearing in public feeds is harmful to the platform, and that the value added to the system by the content does not justify its payout . Now yes, this is an entirely subjective opinion.But it happens to be mine and im expressing it with my vote the same way you were with yours when you upvoted the post.
This justification for a downvote might be familiar to @berniesanders, as it is pretty similar to the one he used when he created a great deal of controversy by downvoting a bad and overvalued post by TDV (a downvote btw that i applauded in various comments).
There is another school of thought that says there is a set of rules about what content is appropriate based on the steemit weltanschauung if you will, a set of shared ideas about what material is appropriate in what places and what is not and that only material which violates this set of informal guidelines should be downvoted.
My views tend toward the first model, where a blockchain is a blockchain and a vote is a vote, though in reality the true answer is somewhere inbetween. I posted my justification based on the second model because, for me personally, a post like this is a flag either way, and Ive noticed that very few people actually take the view that bernie does below. Most people think there are a set of rules about what you can downvote and what you can't. I personally think that this post is a flag even going by those rules.
Now you can choose to reatliate if you want by flagging me... the same free and open blockchain that lets me vote against your posts also lets you vote against mine. But i will point out that 6 people flagged you, and of them, you elected to reatliate against the one of the six who elected to do you the courtesy of explaining why he voted the way he did. The next time someone complains that s/he was flagged and the flagger left no explanation, maybe someone will post a link here.