The Swans went ahead in the 25th minute through Jonathan de Guzman before referee Mike Dean awarded the visiting Eagles a penalty with eight minutes remaining when Chico Flores had brought down Glenn Murray, which led to a red card for the Spaniard.
There is no doubt the contact was there but Monk suggests the tackle began outside the area and was full of questions for the match officials after Murray converted from the spot to force a 1-1 draw at the Liberty Stadium.
"Clearly outside the area. It's blatant to see - I've seen it back on TV and the contact's outside," he told Sky Sports.
"The referee decided to make a decision from 60 to 70 yards away. I looked straight at him as well so he never conferred with his linesman on that side.
"The linesman wasn't flagging for anything, and he (the referee) has made a bad decision. He's obviously gone on what on he thought was instinct but how can you see from 60-70 yards? I find that quite bizarre.
"Okay, maybe it was the last man in terms of that (the red card), so I'm not necessarily grumbling about that, but the penalty itself was clearly outside the area."
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball