Boateng was dismissed as the World Cup champions struggled past their Group F rivals.
"Boateng's walking around the place like he's playing Sunday League football," Keane began. "He's been a disgrace. Get him off."
Neville agreed with his former team-mate and added: "Roy is absolutely right. The [Germany] centre-backs have been a joke.
"I mean Boateng, for some reason, seems to think he is [Franz] Beckenbauer, thinks he's the player. He's played under Pep (Guardiola) and started to believe he is a fantastic football player.
"He has been a joke in this first half. He's got delusions, thinks he is a player; he's wandering forward, ambling in the game."