When I joined KDP (kindle) in 07, I loved it. KDP is something only authors and publishers have to look at, so it ain't got to be pretty with all the slick bells and whistles, its just got to be able to upload a cover picture and the book itself, and in the beginning, amazon kept it short and simple and to the point.
It was so perfect in 07 to 12 that you could upload a book with dialup or even over just about every cellphone out there, anywhere around the world.
But amazon wasn't happy with something so simple, easy, and perfect that only authors and publishers had to look at.
They worked long and hard to build into it tons of bells and whistles. They added the latest version of flash, so that most PCs using XP were locked out. They bloated the bandwidth so that it takes 20 megs to upload a 1meg jpg. They crammed 5megs of sloppy HTML fancy formatting bloat into each page so that on most cellphones it takes minutes to load a page instead of seconds.
Most cellphones can't do flash anyway.
It looks intentional and it reminded me of a highspeed internet company that put 6megs of graphics on pages aimed at getting dialup users to switch to highspeed... the only problem was dialup people had to wait 20minutes until the pics downloaded before they could tell the info they really wanted was on another link.
As an indie author, I have been on a bean and rice diet for the last six years. I can't afford highspeed. I can barely afford this $30 smartphone and a $25/month contract with a scant 200mb/200min/month plan.
Well, in case I'm not alone in this, let me say this. Firefox (on an android) will let you penetrate the cracks in the Amazon wall of frustration, and it will let you upload covers and content to KDP.
But firefox is a beast of another kind. It gobbles data like you had an unlimmited plan, and it gobbles phone MBs too. And its slow.
But it works, for now.