Battery Facts
As batteries discharge the sulfuric acid (electrolyte) becomes more dilute. Sulfuric acid freezes at a much lower temperature than water so as the battery discharges it is more susceptible to freezing. Leaving a completely discharged battery exposed to weather like we've had the last couple of weeks results in what you see in the picture that opened this thread.
Trojan builds a great battery. So does Johnson Controls...so much so that they are the largest manufacturer of lead acid batteries in the world. (That being said I have always lived the lie that bigger isn't always best) The value of buying a much lower priced product of arguably comparable quality to a famous name brand is for the customer to measure.
Sam's sells no seconds. They are a Membership based organization. Their buyers try to make that value decision for their members on all the stuff they sell. Sometimes the result is amazing. These golf cart batteries are but one example. Check their price on Levi's jeans.
The warranty is for manufacturing defects within the warranty period. Sam's didn't stick Johnson Controls with the cost of the warranty for these frozen batteries. The associate could have explained the whole acid-water-freeze thing to his Member but he probably didn't know. Since he couldn't explain what had happened he defaulted, as he is supposed to do, to "make the Member happy"...it's not a bad way to do business as evidenced by some of the comments on this thread.