Warnock's ire relates to an incident that occurred at a time when Blackburn were trailing by just a solitary goal; with Skrtel shown a yellow card for dragging back Jason Roberts as the strike honed in on goal.
"It was definitely a red card - but he's bottled it," he told the Lancashire Telegraph.
"Obviously, it's at Anfield and it's a big decision and I personally think he's made the wrong decision.
"Jason was through on goal and there was no other defenders around him. I don't see how that was a yellow card.
"It was quite a poor decision - but it's at Anfield and it's a big decision for the referee.
"It's the same at the likes of Old Trafford and places like that.
"It's going to be difficult to get a decision, but I think the referee has got to be big enough to make that decision."