I'm going to shame a cashier for helping another customer
Were you ignored by this cashier? Why are you going to shame them?
I don't want workers helping shity customers.
Cashiers are just doing their duties. You shouldn't judge them because of that.
I am ashamed of the cashier and I'm going to say he is a bad worker that doesn't help customers.
I think you're conflicting being helpful with you wanting to be helped first by this cashier. If it is not your turn yet, you should not be impatient and insult other customers or the cashiers. You should be respectful and be calm while waing for your turn.