IntentionalPun
Ask me about my wife's perfect butthole
IMO it's a discount thing. The Kindle is really well priced, and when they introduced ads, they did discount it.for me it's not about it being on as a screen saver, more the fact you've purchased the product and you shouldn't have to pay an extra fee to opt out. Or maybe it's a discount to opt in? Ads are so much more pervasive these days - in games, on the OS, on paid services...
You can view it either way, but if they got rid of the ad supported version you'd still be paying the other price.