I think you're missing the ideological motivation. It's all about ensuring a healthier system of checks and balances. When courts are forced to defer to unelected bureaucrats, they serve basically no purpose - yet our entire legal system is supposed to be predicated on checks and balances at all levels. By returning the ability of courts to hear and legally judge the merits of law, at their discretion, you help maintain an overall healthier system of checks and balances.
It all comes down to centralization vs decentralization. In a completely decentralized system you will never have an amazing outcome, because there will always be plenty of people doing stupid things - this includes judges. Yet you will also never have a horrible system, for basically the same reason - there will always be plenty of people doing 'smart' things. By contrast, centralized systems can yield a complete utopia under the oversight of socially motivated, intelligent, and highly capable leadership. Yet they can also yield the most unimaginably horrific dystopias under self centered, foolish, and incapable leadership.
So which does one prefer? In the end I suspect this is one of those issues where we all think other people think the same, but they most certainly do not. I personally could not imagine anything other than a system decentralized, to its greatest extremes, in every way imaginable. Because if I look at the political types of modern times "socially motivated, intelligent, and highly capable" are not generally the first words that come to mind.