David Frum set the neocon standard for this tactic when he branded the small number of pundits on the Right who opposed the Iraq War as "Unpatriotic Conservatives" at the outset of that strategic disaster. Fast forward to today and anyone who suggests that
NATO expansion could have been a contributing factor to the current Ukraine crisis, or that the sanctions imposed on Russia are not working and have backfired on a soon-to-be-shivering Europe, or even that the U.S. must prioritize avoiding a world war with a nuclear-armed Russia, is denounced as a Putin stooge.
Warping the debate in this way allows delusional and contradictory thinking to go unchallenged. Thus, we get the argument that Putin is a madman who will kill indiscriminately to achieve his aims—but he is also somehow definitely bluffing about using nuclear weapons. And he's only using that bluff because he's losing the war—but if he's not stopped in Ukraine, he will go on to conquer the rest of Europe. Putin's regime must fall because he has killed or jailed all the liberal reformers and yoked himself to a hardline Far Right, but somehow he will be replaced by a liberal reformer when his regime collapses.
It's nonsensical, and a real debate would expose some of the delusions in this thinking. But we aren't allowed to have one.