This is within the systemd-udev-hal saga.

Currently, Debian Testing and Unstable experience a bombardment of warnings at boot and inability to mount external media such as CDs, USBs etc.
The root case of this, is due to HAL, which was deprecated many years before, is pulled into Debian Linux system, because Debian's kFreeBSD's Xorg depends on it. Even if not installed.

As udev is no longer able to process broken and outdated HAL, it stops working correctly altogether.

If you have Debian, search and remove "hal*" as a quick problem solver.

Now its clear why Lennart claimed ability to break away compatibility and code advantageous. Imagine the amount of issues that would surface due to completely weird systemd on BSD breakages and cries from BSD to fix them for them, requiring Lennart to waste time on everything - except systemd itself.