timppu: Maybe one day you will be glad they did... unless you don't care about the survival of your Steam game library, and desktop PC gaming overall, of course.
I'm honestly not THAT worried. If there's anything the PC gaming community has shown it's that smart people will do what it takes to keep games running on modern hardware. Emulation, fan patches, PCGamingWiki tweaks, repacks, new installers for 16bit programs, whatever. Obviously some niche stuff falls through the cracks and I am not saying everything is smooth sailing, but does it keep me up at night? Not really.
Denuvo actually working on some games for a long while is a lot more scary to me than anything else.