The Overton Window opens on to that which polite people and their polite media are allowed to discuss, and it’s pretty damn limited. Fortunately, the alternative media is not polite. From Caitlin Johnstone at caitlinjohnstone.com:

“The smart way to keep people passive and obedient is to strictly limit the spectrum of acceptable opinion, but allow very lively debate within that spectrum — even encourage the more critical and dissident views. That gives people the sense that there’s free thinking going on, while all the time the presuppositions of the system are being reinforced by the limits put on the range of the debate.”
~ Noam Chomsky
The plutocrat-owned narrative managers of the political/media class work constantly to shrink the Overton window, the spectrum of debate that is considered socially acceptable. They do this by framing more and more debates in terms of how the oligarchic empire should be sustained and supported, steering them away from debates about whether that empire should be permitted to exist at all.