This is absolutely unacceptable and I don't think you're over-reacting. You told us about one incident, but it sounds like there are many more.
Document, document, document. Write down specifics, including dates, names of other TMs humiliated (more for your reference and you should keep that info to yourself), and details of what happened. If there's a pattern - one gender or ethnic or religious group picked on more, TMs from a certain work center, the type of "performance" required - note that especially.
@seasonaldude is correct that this incident could very well be viewed as religious discrimination, and religion is a protected class under the Civil Rights Act.
I think it's ASANTS about HR being a good resource. I'm perhaps fortunate in that I think my store's HR person is actually helpful. Have you spoken to your TL about this? That would be my first option, but that might depend on their relationship with your STL.
I would not speak to your STL about this without a witness. He sounds incredibly immature and I fear that he would not react well. Maybe your TL or another long-term TM who's also witnessed, although perhaps not been a victim, of his behavior. That way, you're not "ganging up on him," but you need to take some CYA steps with this guy. What a jerk.
