I agree - I would have gone with no comma or a colon mark :.
But, I didn’t make it. I only collect the URL’s for narratives as they pop up.
I have a pretty nice Soros-Hillary one BUT the person who made it left out the apostrophe that was needed.
That’s a great meme and I too was sitting there pondering the comma. I think it adds a little pause that makes the timing work better. But it’s definitely against the rules.
It’s a shame that the people who are clever enough to come with these gems aren’t smart enough to have a person with a good eye proofread for them.