Cashiers in US are not allowed to sit because it is 'impolite' but the only impolite things are some costumers that treat these hardworking people like peasants. 
Why would an employee that’s 75 years old pass out during work just because she can’t sit down even when the store is empty. 
Who was the first one to say it’s “unprofessional” for retail workers to sit down?

A human being shouldn’t stand for 8 hours straight that is very inhumane and cruel. Doctors don’t recommend people to stand up for that long. Prolonged and frequent standing, without some relief by walking, causes blood to pool in the legs and feet. Research has shown that prolonged standing might increase the risk of cardiovascular disease.

US is one of the few countries where they make people stand up for more than 8 hours a day.

This should change now. 
If we don’t make a change now, things will get worse later. We are all equal and we all bleed the same, no one should suffer health problems because some multi million dollar company wants it’s employees to stand up to look “professional” this should change and people that have problem with it better shop online and never enter a store again. 
Thank you