I'm going to give this commenter the benefit of the doubt and hope he meant "execrable" instead of "excretable" in this passage:

In fact, graying hipsters telling 20-somethings how excretable ABBA or Pat Benatar or ELO was just drives them a bit further to load those tunes up on their iPODs.

Of course, many people considered the output of the above-named artists to be comparable to feces, so perhaps "excretable" was carefully chosen after all.