European football's governing body (UEFA) punished the outspoken Portuguese on Friday for his sending off and verbal outburst following Madrid's Champions League semi-final first leg defeat to their arch-rivals last week.
"It's excessive," Valdano told Spanish television after Real's 6-2 thrashing of Sevilla at the Sanchez Pizjuan. "Throughout the season there have been many coaches who have made some very hard comments, and the punishments were smaller."
Real have indicated they would appeal the decision but Valdano said the club had only spoken to UEFA through their legal team.
Mourinho, who had belittled Barca's achievements and suggested there was a refereeing conspiracy to favour the Catalan club, remained silent again leaving his number two Aitor Karanka to speak to the media after the match.
"I don't know when he's (Mourinho) going to come out (to speak)," Karanka said. "But as I said yesterday, when things become clearer and calm down a bit, and he sees why all this has happened, he'll come out again."
Cristiano Ronaldo scored four of Real's six goals, taking his league tally for the season to 33, two ahead of Barca's Lionel Messi.
"We are very pleased, the players are motivated and the boss has burned a positive attitude into us to be able to start the next season well," he told reporters.
Real's victory closed the gap on Barca to five points, denying the leaders the chance to wrap up their third consecutive league title when they host city rivals Espanyol on Sunday.
