Is "these who do not know any better" a mannerless person or someone who doesn't know the custom or the culture like tea drinking in this situation? They didn't try to protect the customer, but just forced him to follow their regulation, so I don't understand why "protect" was used here.
ex)While in Japan, I ordered green tea with sugar at a restaurant. A waiter politely explained that one does not drink green tea with sugar. I responded that I was aware of this custom but I liked my tea sweet. The waiter took up the issue with the manager. After a lengthy conversation, the manager came over and said, “I’m very sorry. We don’t have sugar.” Disappointed, I changed my order to a cup of coffee, which the waiter soon brought over. Resting on the saucer were two packets of sugar. My failure to obtain a cup of sweet green tea was due to a fundamental difference in our ideas about choice. In America, a paying customer has every right to have a request met. But from a Japanese perspective, it is their duty to protect those who do not know any better.
Not a teacher
"those who do not know any better" stands for "those who are ignorant about" something included in the wider context.
My humble opinion.