"I think it is a bit of joke," he told BBC Radio.
"It can't be any footballing reasons because for a club that's been going nowhere fast for the last 25 years and to get a manager in, who is the best out there apart from (Jose) Mourinho and then to turn it around and give us a bit of style, dignity and grace ... and he bought some great players and the fans have some pride again in the club ... this is just a joke.
"If Shinawatra thinks we're going to get into the Champions League after one season, he's trippin'.
"I think Eriksson has given the City fans a bit of pride and I think the minute's silence for the game against United was a reflection of that. He's a graceful, dignified man.
"But Shinawatra has now come in and he seems a bit of a nutcase.
"The only thing that would get him off the hook is if he has Mourinho lined up."
Asked about Eriksson's signings, Noel added: "(Rolando) Bianchi didn't work out. But for every Bianchi there was a (Vedran) Corluka, an Elano and a Martin Petrov. Then you see the youth team win the Cup and it's all dropping into place to buy the odd great player and build the kids around him."
On City's interest in Barcelona star Ronaldinho, Noel said: "City fans don't want Ronaldinho. If he can't pull his finger out for Barcelona, he's not going to do it away at West Brom, next season is he? If it's all true, Shinawatra is living in cloud cuckoo land."