Had this end result played out the "normal" way -- and had it not been Wal-Mart -- I don't think you'd be seeing the outrage.
In a normal situation, Wal-Mart (and/or its insurer) would pay all the bills related to one of their insured being hurt by a third at-fault party. And then the entity that paid out the benefits to the injured would go after the at-fault party or their insurer, and the entity that paid out the benefit to their insured would be "made whole" for what they paid out.
If it played out that way, WMT's lawyers could have directly sued the trucking company to recover the actual damages they paid out to their insured. That's the way subrogation *normally* works. Only any damages above and beyond actual medical bills would likely go to the injured (in the form of pain and suffering claims, punitive damages, and lost income claims). Or else you'd see two separate suits -- one from the insurer who paid out and the other from the injured victim -- each going after different types of damages as appropriate.
So in the end, it turned out how it normally did. The one slimy thing WMT did is to NOT use its own lawyers or insurers to sue the trucking company, but instead not helping the injured in the lawsuit but ready to pounce on whatever settlement they received. Even though it's common for insurance contracts to specify they can get their payouts back from any money received from at-fault parties, the *way* they did this doesn't pass the smell test.
