United finished the match against McLeish's Birmingham with 10 men after Darren Fletcher picked up a second yellow card for a soft trip on goal-scorer Cameron Jerome after 84 minutes.
Earlier a linesman flagged for offside when United netted their 63rd-minute equaliser - even though it was an own goal from defender Scott Dann.
"I've not seen a softer sending-off for a long time," said United's manager. "I've been watching (referee) Mark Clattenburg this season.
"He did the Arsenal-Tottenham game. He had to have someone hit with an axe before he booked anybody in that game (yet) he sends a player off here.
"There were some wonderful and weird decisions out there," added Ferguson. "The linesman gave offside for our goal but it was an own goal."
Saturday's result left the champions a point behind leaders Chelsea having played one more match.
"Alex has done a fantastic job, he had players running 100 miles for him today and he has to take great credit for that," said Ferguson.
"It's a difficult place to go to at the moment, it's not a bad point (for us). It's a tough league, it's not going to be easy. Teams like Birmingham have really improved since coming into the division."
"I thought we were much better in the second half and gave Manchester United too much respect in the first," he said.
"We have a powerful unit in the dressing room and these guys have a collective spirit that far outweighs their individual ability. It's a tremendous spirit and as good as any I have ever worked with."
