Ha, Jesus H Christ.

I'm actually not sure what they do with oil when you drop it off at a recycling center. I'm guessing they clean it and re-purpose it. It's not like it's unusable. It just has impurities from the engine wear and ignition. Remove those and it should be good to re-use, if not for engine oil then at least as a source for other petro-chemicals.

Dumping it back into the group seems like the dumbest way to dispose of it.