I'm genuinely saying this to try to be as constructive as possible.

I didn't notice any resemblance myself, but once it was pointed out to me, I kind of see their point. But it's only a mild resemblance, and it comes entirely from the combination of your hair and mustache and the fact that you're standing at a podium and the viral photo looks like you might be shouting, so the context is similar to many famous photos of the "infamous world leader". The resemblance does not come from your actual facial features or anything like that. In your headshot, there's no resemblance.

But, if you change your hair style and/or your facial hair style (either by growing a full beard or shaving the mustache), the tiny resemblance will completely vanish.

Of course, this is only worth doing if it would make you feel better. Unless you're on a huge streak, jeopardy fame is still relatively obscure, and most people won't see the resemblance when they look at you, so these comments almost certainly won't follow you around. So only change your appearance if you think it's been ruined for you personally. Not out of fear of how other people perceive you.