It's just one of those things that people do at conventions. Watch the Q&A segment of any panel and you'll see similar things. For instance, during a Q&A segment at a Minecraft panel some kid just chanted "Kappa! Kappa! Kappa!". It's asking someone a question who is really popular and that you really like in front of a group of hundreds of people (video will be uploaded to YouTube and get hundreds of thousands of views). You have to try to be the first in line at the mic so the time doesn't run out before you get there, so many people don't have a question prepared or they have generic questions that the panel has been asked hundreds of times (possibly asked already during that same Q&A). Of course, the nerves are crazy and, let's be real, most of the people that attend these conventions are extremely antisocial. What's an easy way to get a laugh from the crowd (possibly the panel) and not look like a fool? Say or ask a popular internet joke like "Are traps gay?". The panel should have just shrugged it off if they didn't wanna play along. The crowd laughed. It's not trolling, it's just something you do at cons (especially during Q&As)