Amen and amen and amen.
Let the kids play. It took guts to get up on stage in the first place. Blast them with internet shaming and they may never play again. Let them play, and let them suck, and they can keep playing until they figure it out and don't suck, and then watch out. So some kids have already figured it out at this age. Well, good for them. Doesn't mean these kids won't figure it out tomorrow.
By the way, there's a video interview with the Worst Band in the World. They're under no delusions of grandeur. Actually, you have to admire their spirit. Not that I want to sit through a gig with them, but they're loving what they do.