As an Amazon affiliate who has done quite well with it, this is definitely a gutting.
But... if I'm being honest with myself, it also seems kind of reasonable. I think their original plan was pretty generous. I was kind of expecting this to happen at some point.
Was this this first you heard of the change? I'm not sure how old that link is, but to say on Feb 24th that your rates as of March 1 are going way down is a pretty tough pill to swallow.
If you aren't on a private contract with custom rates already, you aren't swimmin' with the sharks. Big affiliates heard about this a couple weeks ago, and likely had their contracts updated as a result.
But... if I'm being honest with myself, it also seems kind of reasonable. I think their original plan was pretty generous. I was kind of expecting this to happen at some point.