Vettel courted controversy in Baku on Sunday when he reacted to a perceived brake-check from Lewis Hamilton by pulling alongside the Brit and giving him a whack.
Calling Vettel “crazy”, Lauda added: “Sebastian said he didn’t do anything wrong. This is his normal reaction.
“He is still somewhere else in his brain.
“After three days hopefully he realises.”
Arrivabene, though, is refusing to get drawn into a war of words with Mercedes or Lauda.
“Lauda can say whatever he wants,” he told Sky Italia.
“Sometimes he speaks for himself, sometimes he even talks to us.
“But as I said before, we are silent.
“We work and we let Lauda talk.
“He has his points of view, us ours and we’ll see you in Austria.
“He will continue to speak, we will continue to listen to it. Perfect. There are still 12 races to go.”