The purpose of the community wiki, in it's most basic explanation, is for the community to contribute together on a post. That's why the free edit barrier is reduced from 2k to 100 (sans-bonus) and that's why the percentage of the top editor is listed. It's a post where the community should be able to contribute chunks of information to the answer and make it one combined answer.
Again, it wasn't intended to be used to make you feel ok with using a comment as a basis for an answer. Either you feel bad using a comment as a basis for an answer, don't answer it. Or you don't care, if so, make…