Unethical behavior does not become good just because it happens to hurt "bad people" (or more accurately, companies bought by bad people).

Using a sword to stab someone is evil, therefore, stabbing someone who is stabbing me with a sword is evil?

Another factor is that Amazon is big enough that crawling a minor website under their umbrella for a noncommercial project is unlikely to notably affect them.

Stabbing people with swords is evil, unless they are so big that to them it's at worst a light poke with a fork