Redknapp had the last laugh on his old club with victory at St Mary's.
He said: "It is the first time I have been back here. Everybody gets it when they go back. Scott Parker was getting boos at West Ham.
"When you look at what he did for them, it is incredible.
"It is part of the game now. It did not used to happen in my day.
"We did not behave like that but people have a different mentality. They sing songs to people which are disgusting.
"There are lots of good football supporters but there is a minority of idiots and you should not lose sleep over them."