What makes this all the more ridiculous is Lynn's inept execution; we've just recently witnessed a strip that makes it look as if Mike is complaining about the unfairness of his only having to rake a handful of leaves when John gets to do the whole yard but that little absurdity is just the tip of the iceberg. After all, most of the crap that litters Mike's environment is stuff that they bought him so as to make up for not having all that much when they were his age. If Elly didn't habituate him to the idea that he needs to be stuffed with stuff in order to rate as a human being, she wouldn't have to hector him to clean up his surroundings.
The pinnacle of absurdity, however, is that when Mike actually does become a freeloader who contributes nothing more than chaos and overcrowding, Elly falls all over herself to accommodate his every foolish whim because he's got a wife and children to wave under her nose. About the only person told to clean up her space is that Martian; my guess is that John is still smirking "Chee! How were we supposed to know that Mike and Dee used the rec room to store their stuff?"