By a verification service owned by epic games apparently. So not fortnite but its not a super stretch.
Better analogies would be Azure as "I have to use Windows" or AWS as "I have to use the Amazon store", which sound a lot less ridiculous than your analogies.
Imagine if I said "I have to pilot a 747 just to change the temperature of my house" (because Honeywell makes both passenger jet avionics and thermostats).