Coyle - speaking at a lecture for coaches at the Scottish Football Association - believes it is wrong to question the integrity and motives of officials.
"I've moaned about referees like everyone else and I've taken the opportunity to speak to them to get explanations 20 or 30 minutes after the final whistle," he told the Bolton News. "But I don't envy them their jobs because refereeing is the toughest gig in football. Players are athletes and they've become quicker every year, therefore the game has become quicker.
"Unfortunately, the referee still has that same millisecond to make his decisions, and that's why, with play speeding up and the pitches also becoming better and faster - in England, anyway - that also makes it harder. You and I could watch six replays of an incident and not come to the same decision, so refs have a very difficult task."