I honestly don't understand any of those comments that question his decision to pull out.
Remco felt suboptimal, he pushed hard in the TT and besides some problems with setting the pacing strategy (because of the wind becoming more of a factor), he obviously couldn't push the numbers expected.
So in the evening, the covid test turned out a positive Whether or not that test was done because of the fact he didn't feel well, or because they just planned to do a test after week 1, doesn't matter much.
He felt suboptimal, returned a covid positive test, and even if he felt reasonably well (enough) to continue, you just don't know how it will evolve, and more importantly, even when you don't feel anything, doing the Giro = an incredible assault on the system and this shouldn't be done while fighting a virus. You can easily destroy your resistance against a virus by exhausting your system, and this can in the long run make you much, much worse.
In any way, Remco pulling out doesn't make this Giro less interesting (for me). I still enjoy the battle, the landscapes, the racing,... Maybe the race will be more open now?