Considering this is firmly aimed at water-cooling or AIO, I don't see the problem. Sticking an air cooler in this to me is a little like sticking a 1.2 engine in a Porsche.
Only it's not... well, not according to Lian Li or DeBauer. Their product page mostly talks about air cooling potential (it mentions rads though), and virtually all the official pictures there of the case show air cooled builds, save for one of an AIO. I agree that this case would look better with water cooling (many cases do though), and it's a great case for that purpose, but it clearly isn't "firmly aimed at water-cooling". They have other cases which have been marketed far more heavily towards water-cooling enthusiasts. Besides, at this price point and with a steel/plastic construction, it's hardly the 'Porsche' of watercooling cases.
Most importantly though, based on the GN review, it is actually a great case under just air. He's only using a mid-range Core Frozr and with that front filter removed gets chart topping results! It's just a shame top end air coolers can't be used as it would perform even better then. What's more, they're losing countless sales to people who already own NH-D15 or Dark Rock coolers, who are hardly going to get rid of those and buy a mid-range one just for this case.