Ferro14, I will have to take some time to do some additional checking on "small quantity exceptions" to the legally required labeling on shipments of hazardous materials, but the lack of proper package labeling I see as more of a concern than your ruined carpet (although I understand your priorities differ).
It is possible that you have legal recourse but not for the reasons you suppose.
Edit to add: I recommend you save all packaging material and consult with an attorney in your area.
There can be harsh penalties for those who violate federal regulations on the shipping of hazardous materials. Amazon.com has been fined a couple of times recently for failing to properly follow hazardous material labeling on their air-shipped packages, for example, and their failures could have had catastrophic results.
After a personal review by an attorney in your area, you might find the recommendation is to inform Walmart and FedEx and the Department of Transportation of the noncompliance with the law.
A civil action is a potential possibility for you, hence the need for you to preserve packaging and have evidence of damages.
Household bleach (sodium hydroxide) is cited by the DOT and the IARC and the EPA as a special health hazard substance, and, while not on its own a flammable substance, it can lead to the combustion of other substances.