I don't own any anti religion or anti theism T-shirt, the main reason being that wearing one brings me no benefits, I don't like to reveal my private opinions to strangers, and I dislike the general aesthetics f most of those T shirts. Just like I wouldn't like a Christian wearing a T shirt saying 'Atheists are going to hell' I don't see much point in wearing one of those. And people don't bother me in real life because of religion and god.
Whoever fights monsters should see to it that in the process he does not become a monster. And if you gaze long enough into an abyss, the abyss will gaze back into you