Ask HN: Please explain ("controversial penalty")

This article

http://hackflow.com/blog/2014/06/22/why-every-language-needs-its-underscore/

contains the following text:

P.P.S. Please stop commenting on Hacker News, a controversial penalty is killing this post. Use reddit thread instead. Sadly, HN is not a place for discussions anymore.

I do not understand what he is talking about. In particular, what is meant by "controversial penalty". Explain?

BTW, the HN post apparently being referred to is here:

https://news.ycombinator.com/item?id=7927578