Should I buy them or leave them?

Expiration dates on food are for the store....not you. The food industry...all aspects of it depends on constant stocking to make sure they always have a place to sell their products. If no date was printed on things a store could let whatever sit there on a shelf forever and that would mean the cookie people..whatever---would not have a constant need to produce products. Exceptions are meats...produce...dairy...baked goods. But canned veggies....things like that are good to eat with no problems for a year + after the date says it needs to leave shelves.

I’d probably post it on Facebook that they don’t check for expiration dates in that store.

Was that a "best before" date or a "use before" date? There is a difference.

Try should be ok