Saints were leading the reigning Ladbrokes Premiership champions 1-0 at Celtic Park when MacLean, who scored St Johnstone’s goal, got into an altercation with Kieran Tierney.
Replays appear to show the McDiarmid Park striker swinging his arm toward the Celtic full-back as the two players tussled with each other off the ball, though little contact appears to have been made.
Collum decided to book MacLean for his part in the coming together, though certain members of the Celtic support thought the punishment should have been more severe.
@TamtheTim1888 said: “Whether he connects or not the intent is there. Red card all day long. Or a night in the cells.”
@McgrottyIain wrote: “It’s either a red or nothing. Can’t be a yellow. Straight red for me.”
@davidkerr1970 added: “Not a lot of contact but it’s the intent that matters.”
Though @joebhoy1989 countered: “S**** quality but looks more of a turn of the arm trying to free himself? If it was other way about I’d be appalled getting a red.”
Celtic rescued a draw from the fixture when Callum McGregor netted an equaliser with ten minutes remaining.