There are direct quotes from Kinnear. He's either lying outright (and if so I'd expect the club to have something to say about it) or it's true.
It speaks volumes about Kinnear's past record of lies in the media that people are still clinging onto the belief that this might not even be true. If it was Roeder, Bobby, Souness, Keegan, or anyone else saying this, then people would accept it as 100% fact, provided there is quotes in the source ofc.