Proposed solution: remove the karma penalty and do exactly the same thing we were doing before. That is, if someone is pretty sure that they will not benefit from reading the replies to a particular thread, they don't read them. No disincentives from posting such a reply needed. What is the problem with that system?

Edit: As of this edit, if one more person decides they don't like my comment, then no one can tell me why they don't like my comment without loosing 5 karma. One of many reasons the new system is terrible.