Amazon is indeed immoral... from the
removal of books from Kindles in violation of their own TOS, to
removing LGBT books from rankings to
banning sales of ebooks that they allow in print, and
the way they (mis)treat their workers should be criminal.
However, their tax practices, although obviously being based on loopholes not intended to apply to companies of Amazon's size and scope, aren't one of the problems I have with them. I'd like the laws changed to close those loopholes; I don't think they're unethical for taking advantage of them while they exist.