Mohsni was shown a second yellow for a clash with home manager Gary Bollan as the teams headed for the tunnel following Rangers' 1-0 win.
The centre-half will now miss Sunday's trip to Stenhousemuir, and McCoist said: "I'm disappointed as it probably could have been avoided. Bilel's an emotional player and an emotional guy.
"The referee has told him he has received a second yellow though for acting in an aggressive nature and that results in a red card.
"There are a lot of things in his game that are different to Scottish players so we'll sit down in the next couple of days and have a chat."
McCoist detected a hostile atmosphere in Airdrie just days after he got the same impression at Dunfermline, where the League One leaders won 4-0.
He said: "There was an attitude around East End Park and around the stadium tonight which I don't think is necessarily a good attitude for women and children to be involved in at a football game.
"Let's just leave it at that. But if we're going to have to handle it that way, we are going to have handle it that way.
"I'm a big enough boy and have been around Scottish football long enough that the fans and opposition aren't going to open the door and let them trample all over you. That's just the way it is."
Bollan said of the Mohsni incident: "I was just trying to get my players off the pitch when he gave me a mouthful. "I have no idea (what it was about)."