Oh, there's been bitter fights before. Just think about the emacs vs vi wars. Or, closer to systemd, the whole "SysV init" vs "BSD init" differences certainly ended up being things that people had "heated discussions" about. Or think about the desktop comparisons.
I'm not really sure how different the systemd brawls are from those. It's technical, but admittedly the systemd developers have also been really good at alienating people on a purely personal level too. Not that that is anything particularly new under the sun _either_: the (very) bitter wars between the GPL and the BSD license camps during late-80s and early-90s were almost certainly more about the persons involved and how they pissed off people than necessarily deeply about other differences (which existed, obviously, but still).
Torvalds was asked if systemd didn't create a single point of failure which makes a system unbootable if it fails. "I think people are digging for excuses. I mean, if that is a reason to not use a piece of software, then you shouldn't use the kernel either."