I don't think it is so much shaking a fist at God so much as sticking a tongue out at "Christianity" and "oarganized religion." I have two good friends who are left wing, anti-Christian, pro-choice feminists, but have no problem talking about God or Jesus. But don't get them started on Pat Robertson...
Yeah, good point. You might want to pick up the book
Blue Like Jazz for a fresh and innovative perspective in regards to folks in this mindset. I have given out several copies to those who are college age and it ususally hits home.