Given the perspective you described, I would consider the actions of the company to be systematic mass murder who the legal system fails to stop, and the actions of the shooter to be community defense against a mass murderer. They’re certainly not equivalent, and I don’t see what the benefit is of treating that defense equally to even one callous for-profit murder.

The problem isn’t that exceptions are made and therefore all crimes should be treated in an ignorant vacuum. The problem is that the idealist legal system doesn’t even consider indirect suffering as the violence it is, because the legal system is ultimately beholden to the power of capital (money buys politicians and the media power to make them win, politicians write laws).