The distinction between derailing and "understanding the values and otherwise" is contestable and in fact routinely contested by debaters - and there is of course no de jure or de facto rule that the person who goes further in trying to critique assumptions and structures wins.

The style of "critique is inherently bad" argument made by this article is also perfectly possible to make within debate. But it's not common, less because of biased judges (who certainly exist, in all directions) than because it doesn't stand up to scrutiny very well in context. Policy debate isn't a great truth-finding endeavor, but it is ruthlessly competitive and as a result pretty effective at weeding out arguments that, like the article's, rely on a low-context audience who have heard a lot about out of control woke college students but haven't just watched a bunch of rounds of vigorous dispute over everything from hypothetical policy details to the boundaries of the year's topic to, yes, critical theory, with practiced advocates on every side.