The site guidelines ask

> Please don't comment about the voting on comments. It never does any good, and it makes boring reading.

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

I don't have any insight as to why this particular comment was down voted. (Edit to add: I suspect it was down voted because it misquotes the source material.) If it's something you're really interested in looking into more in general, I suggest searching HN for other discussions on votes and taking some more time to think about what might cause someone to down vote, whether you agree with the possible reason or not.

As an aside, just because a comment is true doesn't mean it's somehow immune to down votes. Comments in general should be civil and constructive.