Austin has the reputation of being not your typical Texas town -- it's more liberal and more secular than the rest of this Bible Belt state. Perceptions notwithstanding, there's plenty of religion going on in Austin. You can see it from the street.
Antique Judaica is a micro-niche in the art and antique world. There are about 15 million Jews in the world, but only about 700 active collectors. One would think that with such a small market base, there would be almost zero demand for antique Judaica. It's actually quite the opposite.
Getting moved around doesn't happen only to paintings. Many crucifixes that once belonged to churches now hang in front of the "neutral" white walls of museums, along with easel paintings and other things.