This happened to me when I was younger. I had an idea that could best be described as Uber, years before Uber existed. I worked hard on analyzing this idea, preparing all sorts of financials, enrolling in an incubator program to understand how to pitch, getting help everywhere I could.
The incubator held a pitch event that would be attended by a range of people from different professions and judged by a panel of their choosing.
I made my presentation. It went very well. Until one of the five judges essentially took over. Up until then I had received reasonable questions and offered reasonable answers. He chose to be brutally dismissive. I don't know his background but the guy attacked at such a level that no other judge asked any questions. It was truly distressing, to say the least. Once the firing squad treatment ended I said "thank you" and left the auditorium.
I must have been obviously fuming and the attack must have been obviously unfair to some in the audience because an executive from UPS (the shipping company) decided to follow me out and talk to me. After calming me down he said he though my idea was excellent, that it needed refinement and that I should not give up on account of that jerk. Still, I was rattled. Definitely.
I was too young and stupid to process that event for what it was: A jerk being elevated to judging startup ideas who was there to feel superior by hurting people. Again, I was too young to process that and I did not have anyone around to help me get past it. I quit. I abandoned that particular dream. All because of that one jerk.
Now, many years later, I wish I hadn't. I wish I had been equipped with the wisdom to dismiss him for what he was and move on. Again, too young, didn't have enough experience and this guy was at the right place and the right time to destroy me. And that he did.
Thankfully my career moved on. I have nothing to complain about. I sometimes wonder how much of that goes on in the startup scene. I wonder how many great ideas (or potential entrepreneurs) evaporate because of assholes who want to "seem clever".