The switching cost between launchers on PC is negligible, compared to phones where it's a massive undertaking. That said, in the context of user freedoms I think it's fair to not support Epic (in part, for their actions towards exclusive games) at the same time as supporting Epic (in part, for their actions on mobile platforms).
I don't think it is. While I may agree with the goal of open platforms, I don't for one moment believe that Epic cares at all about that goal and I do not believe their method of intentionally violating TOS and using propaganda to direct a raging horde of children at Apple is the right way to go about it.
It's funny that people gang up on Epic Game Store exclusives when Steam has been doing exclusives for over a decade. Not only Valve games, but almost every AAA game that isn't made by Ubisoft or EA is basically just a code to unlock the game on Steam. You need to run all the updates through Steam, microtransactions through Steam, start the game each time by Steam. You can't live without Steam for most AAA games.
That's on the companies making those games, Valve doesn't pay them for exclusives and even allows developers to sell Steam keys on other storefronts without taking a cut.
No sane app development business would do this when half of their potential customers are on an iPhone.
I'd rather vote in legislators that will maintain the existing laws of the land, which state that you can't use your Apple-sized market power to keep competitors from doing business.
What do you support?