No one said to be rude, let alone cruel, to service people. Talk about a weird mindset.
No one said anything that evenr remotely implied the cashier has the ear of the ceo. Talk about a weird mindset.
It's entirely valid, in fact it's positive, being helpful by being informative, to tell a business what you want or why you are not going to buy their product, instead of simply not buying their product.
It's for damned sure valid to tell them what you would preferr if for some reason you are forced by circumstances or priorities to buy their product under duress.
This whole comment is only 2 sentences yet manages to have like a dozen different facets of weird mindset if you unpack it all.
The original comment talked about intentionally creating a “hostile atmosphere”. Doing that for no other reason than making yourself feel better is rude and cruel to the people who have to deal with your hostility.