[HashThis]

This is a good post. Why is it grayed out?

[simplecomplex]

Nobody knows. HN has downvotes for a secret group of users. HN weights votes using a secret algorithm, so some users may have the ability to grey out posts with a single click.

[abdullahkhalids]

All you need is a certain amount of karma - which you currently don't have. There is no other criteria.

https://news.ycombinator.com/newsfaq.html

[netfl0]

Now your post is grayed out.

Someone is watching...

[SuoDuanDao]

I was tempted to downvote both of you just to cause untargeted suspicion :P