I had to look up "Sapio-Demisexual."
Your reply does not change my opinion of your original post.
The only way you are going to find out if the guy is intelligent is if you talk to them. The only way you are going to talk to them - in a bar - is if you draw attention to yourself.
Maybe back then you didn't know you were "Sapio-Demisexual" otherwise, I question your judgment in going to a dive bar to meet someone you'd find attractive. I'd say a book club would be a much better way.
Back in my single days I didn't go to bars unless it was just to look for a hookup, for exactly the reason that it's a loud bar where a meaningful conversation is not going to happen.
Ironically I met my wife in a bar and we are very happy together for over 21 years. I went to the bar with friends to hangout, not looking to score. My wife was the bar manager (i.e. also not there looking to date).