The other account has lower karma (< 40). So I don't know exactly how downvotes work here at HN, but I've read a bit about how other people say they work (i.e.

The other account has lower karma (< 40). So I don't know exactly how downvotes work here at HN, but I've read a bit about how other people say they work (i.e. gray out the comment + reduce the downvoted user's karma a little bit).