Because it has experience with unions.
As far as I'm concerned, any union-buster is an enemy of humanity, against whom any atrocity is morally permissible.
There is an obvious reason why Amazon has opted to respond so aggressively to unionization efforts in the United States. Its European workers are unionized and are actively demanding better wages and working conditions. For example, in Germany, unionized Amazon workers walked off their jobs for higher pay in November during the peak holiday shopping season. Last year, Italian workers went on strike for 11 days to win an extra five-minute break to ensure good hygiene in light of the pandemic. And, in the spring of 2020, French unions demanded that Amazon suspend all activity at its warehouses in the interest of worker safety during the early months of the pandemic. A French court ruled favorably, saying that the company had to suspend deliveries of all nonessential items.
Further, union leaders and unionized workers from various European nations began collaborating with one another last year in what Business Insider called an effort to “swap notes… on how to pressure the retail giant to improve their working conditions.”
This sort of European union activity and cross-border worker solidarity is exactly the type of scenario that Amazon does not want to see replicated in the United States.
As far as I'm concerned, any union-buster is an enemy of humanity, against whom any atrocity is morally permissible.