Hmm. It is not a big story and it is misleading, but it is not a non-story. If Amazon grants itself a right to my bandwidth without compensating me that is not insubstantial. Not all of us ride on fiber with unlimited everything. Giant corp skimming resources off of little guy. And we don't even know if that is all they are doing yet.
It's arguable that you get compensated by having access to Alexa at no cost. Even though the two don't necessarily have anything to do with each other, Alexa is essentially a loss leader (unless it's folded entirely into the sales price of the Echo speaker, which I doubt).
In that sense, the economics seem pretty comparable to ad support on the internet to me: By letting advertisers use your internet connection, processing power, screen space, and time, you get access to content that would otherwise be behind a paywall. And ads use up data caps and congest networks as well, in some cases even more so than the actual "pay"load!
I know that some people object to ads on the internet on the same grounds (usage of one's resources without compensation or consent), but this is a wholly different story from the liability issues that operating an open wi-fi hotspot can cause.
Alexa is another sales channel for Amazon. The fact it can be used for setting timers, toggling lights, and looking up stuff from Wikipedia is all tangential to making Amazon your default choice for ordering something while cooking and paying for Prime so you can listen to music.