Trapattoni only decided to retain the player for Tuesday's friendly against Oman after he made a grovelling apology, and the Italian admits had McClean been playing for a bigger country, he would have been axed.
"Another manager, English or German, would have said 'take your bag and go home', but I might need him in the game to score a goal," Trapattoni told a press conference.
"He was mortified (when he was pulled up in front of the squad). If he could have, he would have eaten his words. He was very apologetic.
"I said to everyone this is not about respect for the manager, this is about respect for everyone. I said the players are your colleagues.
"The matter is closed now. With the young we need to have patience. Sometimes they say things they regret."