Yeah, I'm sure the Danish forums are full of their fans saying the same thing, especially having lost the game.
But they can't just mull it over for a while and then try to squeeze the game in when they can. As said on here, the final group games have to kick off at the same time, for a start. And then, whoever qualifies from this postponed game would have a much shorter recovery time before the knockouts and be at a disadvantage. And organising all the stadium workers/media plus teams and backroom staff in a pandemic and keeping everyone as safe as they can from covid must be a nightmare even with months to prepare, let alone at short notice.
That's the reality.