How is it behind anyone's back? Fedora made the change by updating to a new systemd and accepting it's defaults and behavior. They could have easily changed back or to whatever else they wanted with a one line config change.
It was clearly Fedora that chose this setting for their distro, not Lennart (of course he's always personally is solely responsible, right?). Fedora just decided that as of 31 it was fine to use systemd and also have big PIDs.
It's also not a problem because behavior related to PID management is a major part of the job for the init daemon. Like it or not, init is central to the bring-up and management of userspace and processes, so after the kernel or maybe glibc, it's one of the few other packages that should reasonably own this setting. So it's not like systemd in this case is overextending into questionably relevant areas.
But vitriol for an upstream changing it's way of doing things? vitriol for an upstream even having a preference? vitriol for any reason at all about a triviality like this? For what's pretty clearly a better preference at that?
This tells me that there is baseless irrationality and unwarranted emotions going on to a level that I find absolutely shocking.
Bottom line: If someone makes something and gives it to you for free, you are way out of line to criticize them for making it they way they wanted to. You are looking at a Fedora Gift Horse that contains a systemd Gift Horse in the mouth. And then complaining that, while arguably better, it's wrong in principle for them to have given it to you they way they did.
If you don't like the thing that Lennart and his folks made and gave to you for free with no strings attached, stop using it! Go make something better. Fix it! Fork it! Stage a systemd maintainer hostile coup and lead them to push out only your desired preferences if you want.
You don't like that Fedora used systemd and allowed them to set this setting, and then gave it to you for free. Same answer.
Don't spew anger about things you got for free that no one made you take.