Presumably somebody involved in deciding budgets, a politician perhaps, or somebody with a rather political role in the hospital. Whoever they are, in most cases they're balancing ventilators against test kits or against hiring more doctors or against letting people keep more of their paychecks, or all kinds of other things which might indeed be more important for the patients/citizens/etc...

There's no fundamental reason why they have to be in a position where screwing the people who receive the care would ever be considered the ideal option. But that's how it is when you have a group of shareholders who have no stake in the quality of care. Thompson opted into a conflict of interest which need not exist in order to provide insurance.

More likely they balance the need to increase healthcare taxes against their chance of being reelected.

Sure, and that's not exactly comfortable (maybe "reelected" shouldn't be a thing, idk). But if the people reelecting you are also the patients then the particular conflict of interest I'm worried about is not present.

Yes, that's why NHS is so well funded. Oh, wait, it isn't.

Government-organized resource allocation is, more likely than not, bad to very bad.

True, and we need to get our shit together about that, but it's not an apples to apples comparison. A government allocates 100% of the available healthcare funding towards healthcare outcomes. A corporation (in the US) allocates 80%. You can tolerate a sloppier slicing if you're starting with a bigger pie.