I don't really blame them for using Epic Online Services. If it's something you didn't know about, Epic essentially offers a ton of free multiplayer services to game developers--matchmaking, etc. I'd say for a smaller game it's probably better to use than some sort of independent server, because it may be a lot more resilient to being shut down in a year. All of it is totally cross platform, cross-engine and can be authenticated without an Epic account. I've played around with it a bit, but the miserable little game I'm working on isn't ready for a multiplayer implementation quite yet.

I know because I'm typing words on the internet I'm supposed to have a seething fire of hate for Epic because the Steam community told me to, but they actually offer a lot of really good stuff to small game devs for nothing.

The fact that an account is required is the devs fault. They should use the Connect Interface (which lets users ID by all sorts of platform tokens) versus the Auth Interface (requires Epic account). There's tech stuff about it here https://dev.epicgames.com/docs/game-services/eos-connect-interface#differences-between-auth-interface-and-connect-interface