How are you defining "hooliganism" here?
I think bumper stickers are pretty safe on 1st Amendment grounds, even if you personally happen to find them offensive or 'blasphemous'.
Up till very recently in historical terms, the courts in the US defined public decency fairly restrictively and they were aware of the First Amendment. Direct non-argumentative blasphemy would not be tolerated.
Why hooliganism is a peculiar trait of atheist is explained in my first port here, #76
an atheist monument is absence of a monument. An atheist bumper sticker is absence of a bumper sticker. Since that is not satisfying to some atheists, instead of proclaiming their atheism they need to vandalize my monuments or insult my religion.
What about vanity plates? States have denied Choose Life vanities.