Each one of them, individually, had to prove that they had no affiliation with the individuals and organizations from the investigation. That meant extra drug testing, on top 9f submitting verifiable proof that they had practiced at different facilities and that they literally had nothing to do with the individuals from the investigation.
I thought the same thing as you before before looking into it, right before the Olympics. I was like "C'mon, man, that's just Russia. We all know that."
It's not.
If you heard about the original investigation a couple years ago and thought, "Damn, that sucks for any of them that weren't cheating," you are talking about the Russian Olympic Committee.
-foe