[user104658]

There is a genuine QAnon conspiracy theory that high-ranking democrats are an elite band of paedophiles who drink children's blood. This has done the rounds for years. I've seen whiffs of it on this forum... and that is what Biden is referring to. The reporter asked him a question that relates to typical Republican rhetoric about the defund movement, and Biden sarcastically responded in the vein of "LOL I bet you believe the conspiracy theories that we drink kid's blood too."

Right-wingers are latching onto this, pretending it's a creepy comment that "came out of nowhere" and was prompted by nothing, when it was not, it is a real conspiracy theory that does the rounds on far-right conspiracy forums.

Then of course you get the dummy dums all over social media and forums saying "omg wot he on about hahaha so creep" because they're not politically engaged enough to know the actual context of the comment, but casual-politically-engaged enough to still want to flap their gums.