There is a fine point here that is worth noting.
As I understand it, the issue is the AC units, generators, and compressors on the front of the trailer body. Refrigerated trucks have a 53' box, and the AC unit on the front (up to 3' deep) is not counted. The race teams have AC, generators, and compressors in this same space. Shouldn't that be allowed?
Again, as I understand it, the straw the broke the camel's back was when trailer manufacturers started enclosing that section, for looks, safety, security, who knows. But that was the tipping point for the laws. No longer was it boxes tacked on the front, but an additional enclosed area. Some states said OK, others did not.
In any case, several of the teams have acknowledged that the trailers were built in jeopardy of the laws, but done anyway. They skirted the weigh stations at night to avoid detection. I understand pushing the limits, that's what these people do every day. But just as when you push your engine too far and it craters, if you dance at the edge of the law and get caught you have no one but yourself to blame.