UEFA fined their federation 80,000 euros on Thursday and ordered them to play a game behind closed doors, while suspending a number of players from both sides after racist chanting led to a melee towards the end of the game in Krusevac.
The sanctions were met by dismay by a number of notable figures within the game, including cousins Rio and Anton Ferdinand, the latter one of Redknapp's players.
"We've got to stamp down heavily on any forms of racism in sport," said Redknapp.
"There is no place for that in any walk of life and I think they got off very lightly, haven't they? I don't think they really sent out the message they should have sent out.
"They had a real opportunity there to really make something of it, but it is a difficult one.
"You're dealing with a minority of idiots probably in the crowd. You're dealing with a minority of idiots that threw a coin at Rio Ferdinand last week.
"It is always just a few who spoil it for the rest, I don't know how many Serbians in the crowd were being racist or causing problems, it might have only been a small number.
"That is always the problem but certainly stronger action should have been taken anyway."
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