I've received it via the e-mail address I use for KDP, which I don't use openly online. I've checked the e-mail address that I use for my writing and website, and the one I use for most of my online stuff - and they don't have it. So, I'm guessing it's legit.
I must say, I'm vaguely insulted by it, because it's an attempt to drag me into an argument and support Amazon, when, if they get their way, any effect on my own bottom line is likely to be negative. They are a business. I expect them to do what is best for them. However, I'm running a business too. If you want to petition for lower ebook prices, petition my Amazon customer account - where it's logical to assume that we want the same thing. If you send it only to me as an author - that's crazy!
It's like a big supermarket mailing their little suppliers and asking them to petition Big Food Corp to sell the supermarket their food for less. Seriously! It's that insane, and it's an insult to my common sense.
They've messed up PR-wise with this in my opinion. It makes them look petty. Up until now they've done a good job of taking the high road. But, trying to round up people who need you to help make a living and asking them to do something that might make it harder for them to make a living in the long term... Not cool. It's none of our business, so don't send it to our business accounts. Send it to readers/customers. If they didn't send it to the better target audience, then maybe they should ask themselves why they didn't - and why they thought it was a good idea to send it to their authors.
Personally, I wouldn't be surprised if it was the idea of a passionate employee somewhere in the management chain, who thought this would be a good idea & signed it off, and is now answering uncomfortable questions from their manager!