I think they're largely fine with carrying a USB charger, the complaint is that the built-in battery is known to degrade over time. If your device has a removable battery, you can get a new one and pop it in. But when everything is sealed together that becomes a much riskier job.

A lot of people replace their phones on a 2-3 year cycle. If you could get a new battery for $30 and install it yourself in 30 seconds, would people be throwing less phones out?

You'll note that Apple's warranty language (and probably everyone else's) specifically defines batteries as a "consumable part." Given that, it's a bit of a dick move to make them so difficult to replace.