Ronaldo was incensed when match referee Chris Foy booked him for going to ground in the Tottenham box when the Portuguese felt Ledley king had tripped him.
And Modric believes Ronaldo's on-field petulance, as much as his acts of simulation, have no place in the English game.
'He's an excellent player, but he really overdoes the theatrical bits,' said Modric.
'In England, where fairness is especially kept in mind and where a masculine, fair game is the law, such whining stands out even more.
'I don't know what good it will do him.'
The Croatian international believes Tottenham have a good enough squad to bounce back from the disappointment of a penalty-shoot our defeat that saw them surrender their Carling Cup title to a United side they matched for 120 minutes.
Modric was in line to take a penalty should it have gone to sudden death, though a save from man-of-the-match Ben Foster and a miss from David Bentley meant United won with a kick to spare.
Having missed in a shoot-out for Croatia against Turkey in the European Championships last year, that prospect was not without a certain amount of fear for the midfielder.
"Redknapp asked me how I felt. I wasn't among the first five strikers, but I would have had a go if we had gone into sudden-death,' said Modric.
"I wasn't too thrilled about that, because I have to do everything to overcome that fear. There is no point in it becoming a chronic frustration."
And Modric was also unwilling to answer questions his own future at the club he joined last summer.
'Leave those stories alone, I've just arrived,' he said.