[Brightcolours]

Do you mean The Digital Picture, perhaps?

 

2 things about their charts: 

1. I find them useless and often misleading. They simply often show a worse lens look better, highly unreliable in short.
   
2. You are supposed to shoot the charts at a certain distance, the distance depends on the FOV. So naturally, they have to shoot closer with a lens that has a wider FOV. This is not wrong. What is wrong is that they omit explaining that the Nikor VR II, Sigma and Tamrons have such a loss of focal length that the FOV widens significantly.
   

Of course, one should compare the Tamron's sharpness, when shooting somewhat close up, to how other lenses perform with a similar FOV, not to their "200mm setting". You easily can do that, what you can't do is set a similar FOV on the Tamron as lenses which stick close to 200mm close to MFD.