They must be Amazon Prime members.
Not every international person knows what is usual in the US. For example in Germany prices are always including taxes.
My dad ran a restaurant when I was a kid in a decent part of town. I remember him being happy and having all these friendships with customers. Due to economic issues he had to re-open in a worse part of town and offer a more fast-food-like menu. Holy hell, every customer was just itching for an argument about, well, everything. Getting extra free stuff, complaining about price, being very rude, etc. It was quite the eye opener. I can re-experience this anytime I dare visit a Walmart (we dont go there anymore).
This is why entrepreneurs and businesspeople always say to not compete on price unless you have to, but instead on service or quality. Price just leads down to a rabbit-hole of misery and ultimately hurts the customer who, for a little more, could get a vastly better experience. In my personal life I make a special effort not to be drawn to the low end as I tend to min-max things. I fight to go a step or two ahead of the lower-end, and every time I fail to do this I usually regret it.