You nailled it in the last paragraph. It is important to not get angry at customers. It isn’t their obligation to pay you a living wage. Secondly, the company chooses how much the meals are and indirectly how much they rent their tables per hour. If it isn’t viable, they should increase prices.

Customers may be struggling. Could be their first meal out in months. The company invited them in with these cheap prices.

Tipping culture is like “hey, come in, eat cheap. Oh, and please pay our staff on the way out.” You are an employer, not a table rental company.