I don't agree that Walmart is a similar example. They benefit a great many people - their customers - through their large selection and low prices. Their profit margins are considerably lower than the small businesses they displaced, thanks to economies of scale.
I wish I had Walmart in my area, the grocery stores here suck.
It is a similar example. Just like you and I have different options about whether Walmart is a net benefit or net detriment to society, people have starkly different opinions as to whether LLMs are a net benefit or net detriment to society.
People who believe it's a net detriment don't want to be a part of enabling that, even at cost to themselves, while those who think it's a net benefit or at least neutral, don't have a problem with it.
I wish I had Walmart in my area, the grocery stores here suck.