A web site called cafepress is full of boycott Arizona teeshirts.
Cafepress will print any T-shirt you want them to make. They host/sell some pro-Reagan shirts for me, for example.
If you want to see more Pro-Arizona T-shirts, design them, open one of their free stores, and set it up.
Normally, I’d be all for hammering a lefty provider, but this is like attacking the owner of a printing company because he accepts jobs from anyone and some of his customers happen to be lefties.