I don't think NASCAR set this up for Tony, or had anything to do with anything. I don't think any "fix" occurred. I think Tony had a top 5 car, and his team came up with a great strategy, and he's as good a road course driver as there is (I actually started him on my fantasy team this week). There wasn't some grand conspiracy. Tony had a car capable of winning all day.
If you asked me for my opinion (which is the same opinion as most) Denny had mixed emotions for the last several laps about Tony winning this race. Denny is a driver's driver. It's why he's so active in the council. He and Tony are tight. Denny knows what a Tony win would do for the sport, for Tony, for other drivers etc. And so...at pretty much the very last possible moment...said "ah f*ck it" and tanked it. That's all. No massive conspiracy. No NASCAR orders. No other teams or drivers involved. Just one guy doing what one guy felt like doing, right or wrong.
Oh and by the way, there's two pretty significant side effects from Tony winning as far as Denny/JGR/Toyota is concerned. 1) Chase field will now be weakened, since Tony will (most likely) be a first round exit (and all their top dogs are already in). And 2) Kurt and Kevin will be weakened. SHR now has to prepare 3 cars for the Chase, with an emphasis on the boss & his farewell tour, as opposed to only two cars using all the best and brightest minds to focus on, arguably, the two most consistent cars in the field. Some in that camp might call a race winner/Chase participant like Tony "good for business."
You better believe the contending teams in the garage think about that kind of stuff.