The Dons lost 3-0 in the Scottish Cup semi-final yesterday, following up the 1-0 defeat in the Betfred Cup final earlier in the season, thanks in part to a first-half red card given to Dominic Ball.
The former Rangers player was shown a second yellow after he smashed his head into Ryan Christie’s in a sickening first-half collision.
Yet McKenna says his side still feel hard done by after seeing Celtic defender Dedryck Boyata escape punishment during December’s Betfred Cup final despite being guilty of causing a similarly horrendous mid-air head clash with Gary Mackay-Steven.
However, the Scotland defender had no complaints about Thomson’s decision to send off Lewis Ferguson after a shocking two-footed lunge on Tom Rogic.
“I thought the first sending-off was harsh.
“Earlier this season, Gary Mackay-Steven got knocked out after a head injury from Dedryck Boyata and there was no action given against Boyata.
“Christie gets his head knocked in this match and our player gets the booking.
“The way the two of them were handled, it could have been a bit different. Boyata stayed on the pitch, but we lost a man.
“Was Dom’s challenge reckless? It might have been. But was Boyata reckless when he knocked Gaz out? Who knows? It just seems unfair.”