It's true that more code means more places for bugs to hide. It's also true that systemd and it's fans(myself included) don't really care about init freedom.
Obviously, no self respecting FOSSer is going to sabotage alternatives actively, but we don't use or know the alternatives, so there could be subtle bugs.
But systemd does work. It's not what I would call buggy. It doesn't appear to impede performance.
And very consistently, whenever I think "Oh, how do I do X", there's a clean and purely declarative way to do it, that hooks into all the logging and monitoring perfectly.
Systemd goes a long way to making Linux work like an OS, rather than a build-an-os kit.
The people who are against it tend to be very security conscious. Not "I use 2FA" conscious, but "I will wholesale refuse to visit a popular site that I believe is selling my telemetry data" level.
A lot of the others are enthusiasts. They want to control and understand the machines they own, and don't want any black boxes, and they are almost as grossed out by anything "overkill" as most people are by a drawer of urine. They don't care if it's tucked away, they don't like it being there and don't trust it, no matter how well it performs who who did a 3rd party audit.
Systemd seems highly inappropriate for people who really like the old Linux modular kit approach, or anyone who doesn't like big things.
But the majority of big corporate and average home users seem to love it, and I wouldn't want a distro without it.
The arguments against it are valid, but usually only if you share the same values they tend to be based on.