Why bother defending them about this specific issue though?
Either Epic is right, and this pushes Valve to improve Steam performance.
Or Epic is wrong, and then who cares? People will continue to not use the Epic store and continue to use Steam.
It just feels more "defensive" then "defending" if that framing makes sense.
People are fans of Steam (of Valve, actually) because Steam has been a boon for the gaming world and for Linux gaming in particular, in a way others (like Epic) haven't. I subscribe to this opinion. I'm just so glad gaming on Linux is mostly seamless now, I simply don't care anymore for which OS a game was built (within reason... but then again, Windows games are not guaranteed to always run on Windows either!).
Because it doesn't matter, it's a nonsensical complaint to wait 10 whole seconds for your game program to start, in the wake of literally all the other shit it offers. Even if they sped it up, it still doesn't matter.
Epic launcher starting faster doesn't matter because they don't do anything that would make me want to open the epic launcher.