> Is it my duty to protect Amazon or other consumers?

If you follow Kant, the argument is pretty much this: if everyone would do that, nobody could trust any reviews. The right choice, according to Kant, is that which you can want to be made into law for everyone. You don't want reviews to lose all meaning as they're important information for people to learn about the products, ergo you mustn't fake it.

Should you blame them? Yeah, but it's a pretty small infraction and they're a small cog in a large machine, so don't be too harsh.