Wait, who is jealous of Ken?
The man writes for a living about photography. He depends on ad revenue, therefore he tends towards contentious linkbait and inflammatory statements. It's not to say that anything or everything he says is wrong, just that you have to keep his motives and modus operandi in mind when reading him. Sometimes he says something quite incisive, sometimes he says something spectacularly dumb and it's best to assume it's not necessarily because he's stupid, he's probably just winding up one of the many photographic football-teams so that they'll all link to him in a round of crowing or indignation.
He doesn't do particularly scientific tests, because why would he? People read him for entertainment and opinions they can relate to.
For all I know, Mamiya TLR lenses are crap and abominably flare-prone; I've never used one. But I wouldn't take Ken's word for it in either direction.