We detached this comment from https://news.ycombinator.com/item?id=12238910 and marked it off-topic.
Perhaps you should have asked him to clarify under what circumstances he would support the death penalty rather than admonishing him.
I don't believe in censoring opinions I don't happen to agree with. I think that is one of the ideas of the original article.
HN is not all things. It is a site for civil, substantive discussion on topics of intellectual curiosity. A throwaway line suddenly invoking the death penalty is obviously not that—it's just talking smack on the internet. Maybe a detailed argument would have been different, but I doubt it. Pulling that rabbit out of hat is a stunt.
Not all opinions and contributions are equal. It's seductive to feel that they should be, until you realize that it isn't possible to treat all posts equally: if we did, the inflammatory, reflexive posts would win. That wouldn't just tip the balance—it would be a rout, because the people who prefer reflective, thoughtful discussion would leave. On HN we prefer reflective, thoughtful discussion. It's the rarer and more valuable species.
In a technical biological sense, no doubt all plants are equally valid. But if you want a garden you've got to pull weeds.
Like it or not, the death penalty is perfectly within the norms of the civilised world; it's popular even where not allowed.
In this case, the only thing incompatible with civil, substantive discussion was … you.
On HN, over-the-top rhetoric isn't in anybody's interest. It refutes itself and trivializes the subject.