The Manchester United winger was dismissed in the second half of the Champions League match against Real Madrid after his boot connected with Alvaro Arbeloa's chest as they went for a high ball.
The decision infuriated United boss Sir Alex Ferguson and many pundits claimed the Portuguese winger had been watching the ball and did not intend to hurt his opponent.
United were leading at the time of the incident but lost the Old Trafford game 2-1 to go out of the competition.
However, Poll insists referee Cuneyt Cakir did nothing wrong.
He said: "The point people are missing is that the referee is under instruction.
"They meet twice a year and get instructions what to do - and that tackle will be highlighted on a regular basis. They will be told time and time again it's brutality, that you can't tackle like that because it endangers the safety of opponents.
"It becomes serious foul play - look at where the contact is, you'd struggle to argue with that.
"Only one offence has to be intentional - handball. It's not what you mean to do but what you actually do.
"He intended to jump that high with his foot raised - that's intentional. It's unfortunate, he's not that kind of player but the referee was doing his job and it is wholly wrong for us to castigate him for doing his job."
Poll, who refereed in the Premier League from 1993 until 2007, admitted on BBC Radio Five Live: "I saw it as a yellow (card) at the time because I'm not currently reffing - I got caught up in the moment as many fans were.
"But I have spoken to a couple of top international refs and they both said it's a red card in Europe - but they probably wouldn't send them off in England.
"Refs are having to think, 'Where am I? I'm at Old Trafford so it's not a sending off' or 'I'm at the Bernabeu, so it is'.
The 49-year-old believes referees in England are undermined by the Football Association upholding appeals from clubs following the dismissals of their players.
He added: "All too often the FA overturn it (a red card) and don't support the referee - and what hurts you is you are a highly trained, well-briefed referee with a good CV.
"Why is there the assumption that the ref's got it wrong? The FA and disciplinary committees need to look at what they're doing because it's not helping us."