Redknapp: Rooney is a silly boy
The England international faces a two-match ban if he accepts the charge, which would rule him out of United's league match against Fulham and the FA Cup semi-final against Manchester City at Wembley.
"Why is he so angry?" Redknapp asked at a news conference in Madrid on Monday ahead of Tottenham's Champions League match against Real.
"I don't remember Bobby Charlton doing it when he scored," he added, referring to the former United and England midfielder, a World Cup winner in 1966.
"Why do they have to be so angry with the world these young footballers earning hundreds of thousands pounds a week?"
"I respect him a great deal as a player but he's a silly boy and he shouldn't have done it."
Rooney apologised for his outburst soon after the match, saying he swore in the heat of the moment after completing a 14-minute hat-trick.