You can always turn it off. You can always use Gnome Shell over Unity (should anyway as its nicer). You can always buy another operating system. You know, vote with your wallet. Ah, wait...
There has to be a price for free. In RMS world everybody is a hacker, everything is free (as in love) and open and nobody needs to eat, kids grow up not costing a penny. But in my world, I understand that sometimes I'm getting something for free that is actually superior to the paid stuff, and sometimes those giving it to me need to feed a kid or two, or buy their Mrs that new outfit on the high street. And since they don't charge me outright they try different things, one of which is trying to sell affiliate links to Amazon. They don't even force me to do it because I can turn it off. But they do it by default hoping that I won't. Its a revenue channel, albeit probably a small one at the end of the day. And you know what, had I used Unity I'd probably keep it on and do my Amazon shopping via the OS to give something back.
I also understand RMS-style extreme is vital to balance out the Corporate extreme of the software world. But come on man, choose your battles better and you'll have my support. This one is a waste of time.