At least because of this:

* https://developer.amazon.com/mobile-ads

* https://aws.amazon.com/mobileanalytics/

Not as large as Facebook or Google (at the moment ~5% of top Android apps connect to their servers). Apparently, they are going to grow.

Care about what? Someone using an adblocker?

Because they're in the business of selling things, and many of the "things" they sell monetize via ads. It's an indirect way to killing their rev.

Also, yes, Amazon does lots of retargeting/ad purchasing, so it means they're wasting those dollars as well, again killing their rev.

There's no reason for them to support ad-blocking (other than like, being opposed to massive corporations doing nefarious things, but how could THAT thinking infect a massive corporation)

Presumably Amazon wants developers to continue to support their devices. That becomes much harder to do if, given that the market already does not favor apps which charge up front, they are seen as aiding the only other (semi-?) reliable form of raising revenue.

Amazon offers discounted products if you're willing to accept ads on the lock screen.

they do have product ads that can be placed on a website