Think of Systemd like GNU. They stick their name on all the software they make, even if it doesn't require only using their software. E.g. you can use GNU BASH

Think of Systemd like GNU. They stick their name on all the software they make, even if it doesn't require only using their software. E.g. you can use GNU BASH without using GNU Sed. You can use Systemd-boot without using Systemd-journald.