Whether or not you are/were discriminated against is unlikely. However, I wouldn't waste time and money trying to make a legal case from this. No moral or ethical lawyer would want to take this case. If they're to 'ban' you, you'd not be suffering any financial, professional setbacks.
As Set said, don't overthink this matter. They just want patrons to have fun and spend money. People leave or don't participate when one person wins a lot. I'm a 'triv nut', too, and when I play these games every now and then I see a 'ringer'. I watch people get turned off and mercy sakes top buying beers. The 3rd-party the at runs the triv game is there to keep people around and spend $$$.
Btw, on a different parallel...in Las Vegas, in casinos, they throw out card-counters. And casinos are backed up in discrimination legal court cases. Is card-counting cheating? Well, you have done an amazing feat...memorized a few thousand answers to triv questions. Commendable but not plus for their business success.
However, they (private party) have the right to allow those the privilege to play their triv games..and have established certain rules. What do their rules say?