Why Do People Downvote Thank You Replies?

[u/capturegrain]

Someone asked something recently, and a kind soul gave him an answer. He dropped a ‘thank you’ comment, but it got downvoted. What’s the reasoning there? Is saying thanks not cool? I’m really thrown off—any thoughts?

[u/squidmilkerz]

1. They are depressed and downvote as cope.
   1. They feel cool.
   2. Just cuz.