The challenge resulted in Southampton's opening goal and Rodriguez went on to set up his side's second which Adam Lallana converted.
Le Fondre said: "You would have thought it would have been a red card, wouldn't you?
"It's that little bit of luck that you get. The referee did not see it, Rodriguez went straight through Feds and they get a goal."
The result for Reading looks to have all but sealed their relegation but defender Adrian Mariappa insists that they will continue to fight for every point.
The former Watford player said: "Every game is massive now and all we can do is give it everything against Liverpool next Saturday.
"Everyone is just trying to play out of their skins to stay in this league."