BAES make face visors and ventilators for the NHS, but they also make ballistic missile submarines - so does that mean you should refuse one of their ventilators (if you can splutter out the words)?...
I don't particularly care what Walmart does in the US because, a) it's legal in the US and they are still (broadly) a democracy, and b) I'm not an American, or have any plans to live there.
I do care that Amazon is a large employer in the UK, and that they treat their employees (both direct and indirect) like shit, and they make a specific point of structuring their business in order for the whole to pay as little tax as possible - so I don't buy anything from, or through, them.