There are a number of ways that OP's might give an unsatisfactory response to a comment. I often say that they should do some trivial exercise which will show them what is going on; few try, and often enough someone gives a complete answer anyway. Some are like your guys, I think they are generically called Vampires on SE...
I probably used to try to get such people to improve. For a few years I've just been deleting my own comments or answers. I mostly cannot get the kids (sometimes older) asking to behave better, all i can do is make it so that I am not notified of further messages from that person.
one reference:
http://meta.math.stackexchange.com/questions/15139/etiquette-how-to-deal-with-spoon-feeding-requests/15140#15140Etiquette: How to deal with "spoon feeding" requests?
which points to this http://slash7.com/2006/12/22/vampires/