There are no ethical global multinational companies, sorry to burst your bubble. Every other giant retailer is doing the same to employees, vendors, etc.
Walmart really started the race to the bottom, killed countless good paying retail jobs (many union), so I choose to hold them accountable, even if it's irrational at this point given their competition (Amazon) is arguably just as bad or worse.
Costco treats their employees very well comparitvely.
What makes you think I live in a bubble regarding large retail companies?