Walcott was furious after being told Newcastle winger Milner would take the 82nd-minute penalty Walcott had won with a dazzling run.
Psycho reckons Walcott's reaction shows he is coming of age and the legendary England defender said: "The more he comes out of himself the better.
"The way he played I am not surprised he wanted to score. I'm sure James Milner has heard worse anyway.
"He is the penalty-taker and Theo knows that. If anyone was offended I apologise but I look at the reaction as a positive. A year ago he would not have put himself up for a penalty.
"Now he feels a real part of the team. He got me off my seat all night and was a real thorn in their side."
Walcott, 18, admitted: "I was full of adrenaline and wanted to take it but I knew James would score."