I don't foil because I don't want to nor do I need. When I bbq I'm in no rush to "get it done" in a certain amount of time and I can attain the same tenderness without it. So I really don't need it. But many do and I see nothing "wrong" with it. The most important thing is the final product and having a good time. If both are accomplished then what can be "wrong" about that?
People need to lighten up a bit. This is bbq not frickin' Bible Theology.