I think the issue arises from the term 'zen' being used so loosely in western pop-culture that its real meaning has been depreciated. You will find many Zen Masters recommend students practice what anyone else would consider mundane tasks. This is to cultivate right thinking.
When you drink tea, if your whole mind is drinking-tea-mind, this is a "zen state." It is part of the discipline. When you ride your bike, drive your car, wash your clothes, and your mind is single-pointed and _right_now_ this is a good part of what students of Zen Buddhism work to cultivate.
I believe this is the intended usage when people say "zen" in a modern, casual context. It shouldn't cause offense, rather the opposite. When a person has this right-here-right-now-only-this mind it is universally reported as being a positive experience. And people accomplish great things in such a way, or maybe they get just a little peace-mind or relaxation and say "that was great." It doesn't have to be so dogmatic; "this is zen, that is not zen" because it is what this word means in its context that is the question, and it seems good.