Navi refused to play with a sub, and ESL had to bend over.
They would have lost 20% of their points yes, but that rule is made literally made for situations like this (sickness/other reasons a player can't play), they accepted the rules of the tournament by participating the tournament.
So you can either:
1. Stop partying like it's pre 2020 (don't get a corona).
2. Accept the rules.
3. (Apparently) Party like corona didn't exist, get a corona (your own fault), then whine about the rules you've accepted and get special treatment if your team is important enough (I doubt a team like Espada would have gotten away from refusing to follow the rules, maybe that's why ESL didn't make it a rule in their rulebook, because they had plenty of time to do it).