You can feel various ways, but personally, my reaction is "This is the hill you want to die on? You won't win this. No judge will ever order Apple to let you participate in their app store in violation of their ToS. And if they do, it'll take years of litigation."
Still... Kudos to them for this ambitious plan. It takes guts to intentionally kill off your iOS revenue stream. I wonder what percentage of revenue fortnite iOS generated. Perhaps iOS simply wasn't too lucrative. But if it was lucrative, then this took guts.
Remember that struggles for money and power are often dressed up as struggles for morals and righteousness. You start to see that pattern everywhere.
The other side of this is, Apple needs to play this carefully. It has the potential to quickly spiral out of control. For example, banning all games built on Unreal Engine would ignite a real fury, and would make http://paulgraham.com/apple.html true – 11 years later.
Removing notarization for Fortnite on MacOS is another overstep, but it doesn't seem like it will cause Apple to lose the war.