It's pointless noise. Twenty other readers likely also laughed to themselves about the line, upvoted and moved on. The commenter will know if their joke was appreciated with upvotes. Nobody needed an extra comment from the peanut gallery.
HN polices noise very hard, because the alternative is half the site is just the first comment thread from reddit that continuously circle jerks the same damn jokes.
I didn't mean that it "staining less" is the correct formal definition, only that thinking of it as "stain less" rather than "stainless" is a more useful definition to keep in mind, as all steel will stain eventually the right conditions.
