The Hoops boss attended a disciplinary tribunal at Hampden Park and was found guilty, on the back of two complaints to the SFA, of using offensive language towards Saints skipper Jim Goodwin during a match at St Mirren Park on 31 March.
No sanction was issued for the breach of disciplinary rule 203 but a suspended three-game ban from last season was triggered.
The former Celtic skipper will not appeal and thus will sit in the stand for Sunday's potential Clydesdale Bank Premier League title-winning game at home to Inverness.
At his weekly press conference at Celtic's Lennoxtown training complex, the Northern Irishman, who revealed he will offer striker Anthony Stokes a new contract, said: "It is four hours of my life that I am never going to get back.
"It was a complete waste of time and effort. It sums up a lot of things about football in this country; petty, narrow-minded.
"There was a fourth-official stood six feet away from and didn't feel I did anything wrong so I still think it is bizarre that on the strength of two complaints, from a game that was televised all around Britain and which maybe had 500,000 people watching, that the SFA decided to take this on."
Lennon continued: "I am not going to lie (about doing it) but that sort of language is used in every game. I am not condoning it but it is an instinctive reaction.
"What you have now, it has opened up a huge can of worms for the SFA. Me and my staff, what are we going to do, complain about every manager using foul language from now on?
"You only need two complaints obviously before you are hauled up before the SFA so there is going to be a big, big queue of people outside Hampden."