I have mostly stopped using grocery coupons, for all the reasons already discussed, plus DH and I had a long discussion about how using coupons was sucking us into the whole world of seductive marketing, materialism and hoarding. It was freeing to let go of that.
IMO, we are already a nation (world!) of out-of-control consumption; couponing (especially the 'extreme couponing') just highlights the worst of it. IMO, if I get garbage food for free, I and my family still pay a price for it, KWIM? And using coupons gives us a sense of "beating the system" when, in fact, we are buying right into its most cherished ideals. We hunt for brand names, we sign up for corporate mailing lists, we allow the stores to track our purchasing patterns. We become their favorite kind of consumers. We think we're beating them at their own game. We're not. We're playing their game.
By using your same logic, merely shopping at a chain grocery store or any store, really, outside of a mom and pop shop would be "buying into the systems' ideals". Shopping at a mom and pop shop isn't my reality. If it's your reality, that's wonderful, but otherwise, we're all part of the big consumer game no matter how you slice it. Sure, you can have your goals for how you can lower your impact (which I think is great), but until or unless one is fully self-sustainable, we are all part of the "game".