There is an assumption in American politics, embraced not just by Republicans but also the press and too often the Democrats, that legitimacy comes from one thing only: the support of Republicans. So if Republicans want something, no matter how deranged, it is inherently legitimate.
But if Democrats oppose it, or want a policy of their own, no matter how reasonable or popular their position it, it will only be legitimate if they persuade Republicans to go along with it.
There’s a lot of truth to this, and I think it closely ties with the co-opting of patriotism and faith; i.e., everything they support is aligned with god/country, because it only makes sense that it would have to be for “patriotic Christians” to support it. The line of reasoning is a circle.