He's pretty upfront on his website about the fact he shoots Canon FF, Phase One Medium Format, and Fuji. Seems like he has Medium Format, Full Frame, and APSC with Fuji covered. I'm not sure how many other cameras he needs to use. My guess is he just uses what gets the job done so he can feed his wife and kids. Since he doesn't charge for his reviews nor advertise on his site, I'm not sure he considers himself a "professional reviewer." He included a disclaimer about his relationship with Fuji, I'm not sure what else anyone should expect. It's a blog and as such he has the right to discuss whatever gear he wants in whatever manner he deems acceptable. But that's just my take on it. However not charging for his "expertise in gear wanking" sort of absolves him of the responsibility of testing and rating and comparing. Now if I paid someone to tell me what camera I should use then I might expect that sort of tedium. All that said, he does probably consider himself a professional photographer as do his clients something I'm guessing the normal gear comparing experts have in short supply.
And..hey...he did include a wall chart test with a squirrel that had a fake diamond encrusted $. Let's see Luminous Landscape or DPR top that!
As aside, Fuji (and I'm sure Canon and Nikon do this) hired quite a few photographers to try out their cameras. Perhaps they are wanting to see what they can do to improve them. I'm certainly not a good candidate for that but I bet a professional photographer is. I would say from having used the X100S the last two days, they have made some improvements. I might also add that he had quite a few complaints about the original X100 and X Pro.