I make exceptions for really clever ones, but I think these low-effort comments fail the substance test[1]. If you encourage this stuff you'll start to see karma trains like the other commenter tried to start, and it won't be long before you have to scroll past the puns and maymays in order to read anything of substance like you do on Reddit (save for some subreddits that are aggressively moderated for serious replies).
Aggressively moderated subs like /r/askscience enforce the content rule for top-level comments, not children. It works there because you can collapse a thread very easily, unlike HN.
[1]: https://news.ycombinator.com/newswelcome.html