United are likely to face disciplinary action for the seven card haul.
"For Manchester United it's not right," the United boss said after the 1-1 draw at Fratton Park.
"There is something wrong when Manchester United get seven bookings.
"For me, the first foul the referee should have acted on, (Jermaine Jenas on) Cristiano Ronaldo in the first half, he was hacked down and for me it was a red card.
"He's kicked him from the back. He spent 30 seconds talking to Jenas. Up to that point, up to half-time, I thought the whole game was looking like it was going to go to pieces as a football spectacle.
"The referee settled down in the second half but nonetheless, for us to get seven bookings something is wrong.
"But we don't stop trying and in the last 25 minutes we absolutely battered them. I think we deserved a point.
"The commentator said we've dropped two points but maybe we've gained a point."