Kinnear has wasted little time in making his presence felt with a series of free-ranging interviews which have hardly enhanced his reputation as he struggled to pronounce the names of some of his players, as well as managing director Derek Llambias.
Llambias subsequently resigned after learning that the 66-year-old Irishman would assume some of his duties under a surprise shake-up of the club's football activities instigated by sportswear tycoon Ashley.
Former Newcastle striker Shearer wrote in today's Sun: "Where do we start? What I do know is that right now people are laughing at the football club I support. And that sickens me.
"I promised myself years ago never to be surprised by what happens in football - particularly when it comes to Newcastle.
"But this situation really is stretching it a bit.
"While other clubs are all plotting and planning for next season, Newcastle have a manager who has just been totally undermined.
"Alan Pardew has said he will carry on but I am sure it will be a difficult situation."
He added: "As for that announcement, what are the players to think when he can't even get their names right? It's all a PR disaster."
Kinnear met manager Alan Pardew on Tuesday for the first time since he was installed, and the pair are said to have held amicable talks over the way forward.
But Shearer believes Pardew's public silence on the matter is telling.
"His silence on the appointment of Kinnear himself over recent days said it all," Shearer wrote. "But what could he say?
"He is in such an intolerable position.
"He can't come out and slaughter his employers but at the same time he can't agree with a situation which no manager would find comfortable."