It's likely CYA... most expiry dates are. Look at it this way- if it's dated, at least you know you're not buying cans which are several years old already!
I have no idea, but it wouldn't surprise me if Sam's Club insists on some kind of dating, if only to help them keep their own inventory systems straight.
And AFAIK, it does have pretty well an indefinite shelf life. Especially if it's in sealed METAL cans.
Why metal? Because plastic (only the 6# cans are metal anymore, at least around here) lets air and (if the label isn't there) light through- tiny amounts, in the case of the oxygen, but it is slightly permeable. This means eventually, stuff in plastic will go rancid.. and much faster than the same product in glass. In the case of Crisco, that may mean in 5 years, rather than 15 years.....
I learned that the hard way with Miracle Whip. The quart glass jars I bought in 1999 kept beautifully. But I found some on sale in plastic jars (at Sam's) in 2002, when I was getting "low" on my Y2k stash. When I went to use one in 2003 (about 8 months later, after I'd finally used up the last of my 4 year old Miracle Whip in glass- which was still fine), it was rancid and horrible tasting. All three of the larger plastic jars were bad. I was glad I didn't stock up on them for Y2k...
Salad dressings are the same...if you find a great deal on some in glass bottles, grab them. If they're in plastic, only buy what you can use within about 3 months of the expiration date.
Unfortunately, almost everything is being packaged in plastic these days :-(
Summerthyme