There's one born every second, eh?

One thing that's likely to attract downvotes are comments to the tune of "+1", "I agree", or in this case, "good one!". The sentiment can be expressed with the little up-arrow next to the comment you like, and then it doesn't clutter up the thread. HN tries to keep a high signal to noise ratio, and part of that is greying out comments that really don't add anything. FWIW, I didn't downvote you, but that's probably the reason that people did.