The study also showed that Evangelical youth in highly Evangelical communities are watching more pornography than similarly religious youth in non-religious communities, but the effect of a religious community is more pronounced on the porn-viewing of non-religious teens than religious ones.
So ... the upshot is small, evangelical towns contribute to more teens watching porn, but non-religious teens in those towns are the ones watching the most.
When I think of Evangelical Protestant communities I think of middle income to rich folks. Where lots of kids have several devices to access with the internet. Some kid might get counted as three people between his phone, tablet and computer.