Reports of off-field quarrels have been rife at the club in recent times, with Mourinho at the centre of most of those having allegedly fallen out with chief executive Ed Woodward and midfielder Paul Pogba.
The problems appeared to spill out onto the field as United were beaten 3-2 by Brighton & Hove Albion on Sunday, and Ince insists that he can understand why the fans are unhappy with Mourinho.
"Other clubs and fans are having a field day at the minute, seeing what is happening at Man United. They're becoming a laughing stock, and falling behind. Everything from top to bottom is in turmoil, and it shows. Should Mourinho leave? No. Should Man United as a club get their house in order? Absolutely. That's the whole lot. From the top down, Ed Woodward, Jose Mourinho, Paul Pogba, everything is a total mess," Ince wrote in his column for Paddy Power News.
"I can see now that fans are turning against Jose Mourinho, and I can understand why. When you see Man City, Liverpool, Chelsea and Tottenham – they're all playing the kind of football you expect from a Manchester United side. The fans want to see attacking football. They want to see the kind of performances they're used to from United sides, even if the result is sometimes disappointing.
"They're right to be upset, because I don't believe they're going to see that this year either. I watched the game on Sunday, and I physically couldn't see what Mourinho and United were trying to do. There was no game plan whatsoever. When you're managing at Old Trafford, you're expected to play a certain style, and if you're not then there's going to be issues with the fans and the club."
United's next match sees them come up against top-four rivals Tottenham Hotspur at Old Trafford on Monday night.