We don’t shift the Overton Window by dismissing valid criticisms and facts we don’t like.
Except that is precisely how the Overton Window shifts.
The Overton Window is a range of socially acceptable facts, beliefs, criticisms, and opinions. Anything outside that range is socially unacceptable even if it’s valid.
The Overton Window isn’t about what criticisms and facts are valid. It’s about what criticisms and facts we are allowed to debate the validity of.
(For example, the internment of Japanese during World War II. It’s possible to debate the validity of that internment based on various historical facts. But no decent person would have that debate in the first place. It’s outside the Overton Window of decency. Which is why I expect Fox News to platform Michelle Malkin again shortly.)
The American media establishment has shifted the Overton Window in America, Europe, and Australia, further and further to the right over the last decades. They didn’t do it by considering all valid critiques. They did it by platforming and discussing right-wing critiques of society and the facts they were based on - even the invalid ones - and insisting left-wing critiques of society and the fact they were based on - even the valid ones - were unacceptable to discuss in public.
If we insist on giving right-wing ideas the same fair consideration we give left-wing ideas, we are accepting those right-wing ideas into our conception of what the Overton Window should be. And in the battle to control that window, we are disarming ourselves.