"I would love to say a lot of things, I asked the legal people what can I say and what I can't," West Ham manager Slaven Bilic told the BBC.
"It is never a red card and it's the fourth game in a row we are getting decisions that are costing us."
West Ham came from behind in a rip-roaring first half at Upton Park after a clinical Manuel Lanzini strike and Dimitri Payet's superb free kick cancelled out Damien Delaney's early header for the visitors.
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The result was a setback for West Ham's hopes of a top-four finish as it left them in fifth place, three points behind Manchester City.
"I want to commend the players it was a good game of football, open, and we deserved to win," Bilic said.
"When it was 11 v 11 the scoreline was correct. They caused us a threat, but only at set-pieces, then we turned it around," he added.
"If the opponent is better than you OK, but it is frustrating. We aren't going to sink or moan, we will come back and continue play good football."
Palace who are still winless in the Premier League in 2016, stayed 16th, seven points clear of the relegation zone.
(Writing by Zoran Milosavljevic, editing by Pritha Sarkar)
