It makes sense to me, considering how damaging and embarrassing the content was. If they confirm it, they lose plausible deniability in being able to claim it's fake.
For a large period of time there was a coordinated effort to purge everything from the Internet and paint anyone bringing it up as a conspiracy theorist. It's harder to get away with that if you call attention to the leak and confirm it's authenticity.
Perhaps the laptop truly belonged to Hunter Biden. Without a confirmation or proper chain of custody, it's hard to say either way. It's not implausible that an advanced threat actor, especially one backed by a nation-state, could create an elaborate laptop forgery to 'layer'[0] hacked material into a legitimate news story and avoid the hack itself taking centre-stage like in 2016 — of course, this is speculation on my part.
[0] https://www.moneylaundering.ca/public/law/3_stages_ML.php#:~...