I believe Mike Helton is effectively the Charlie Whiting on race day I suppose and works control, and is also the president of NASCAR yes. There is no collection of stewards however. Ultimately rule enforcement and such usually get worked out between Helton, Pemberton (VP of Competition) and Darby (Series Director).
Why take so long? Alternatively, why rush into it? They decided what would happen for the rest of the Texas races very quickly. Beyond that.. I'm not sure there's a precedent for this sort of thing.
In any event, yes there is a "have at it" policy which basically lets racing incidents be racing incidents. In stock car racing given a 43 car field on tracks as short as 0.5 mi / 0.8 km and minimal downforce... there's going to be car-to-car contact - and it's acceptable. Unlike F1 where a slight touch between cars can rip off a wing and ruin a guy, denting a fender isn't a big deal. If you're battling for a position and nudge a guy out of the way, and then he nudges you back on another pass... that's fine.
Intentionally wrecking someone under a caution most certainly does not fall under that realm of leeway.