Oddly...it kinda makes sense having Kermit singing Trent Reznor's 'Hurt.' He's been the happiest figure of puppetry for decades.
I've only heard him complain briefly in a couple of movies before solving the problem and getting cheerful again.
So why not have him performing this near perfect exploration of personal darkness?
Scenes of puppet drug use, puppet puking, and general puppet downard spiral cliche.