Not content to be caricatured by the likes of me (and it is a caricature, which I think we take too seriously at our philosophical peril), Kant responds:
As for those [e.g. Kant himself] who play down or outright deny the boasting eulogies that are given of the happiness and contentment that reason can supposedly bring us: the judgment they are making doesn’t involve gloom, or ingratitude for how well the world is governed. Rather, it is based on the idea of another and far nobler purpose for their existence. It is for achieving this purpose, not happiness, that reason is properly intended; and this purpose is the supreme condition, so that the private purposes of men must for the most part take second place to it. Its being the supreme or highest condition means that it isn’t itself conditional on anything else; it is to be aimed at no matter what else is the case; which is why our private plans must stand out of its way.
Kant, Grundlegung, Ak. 4:396