OK, that's a technical matter. That's not what he's upset about, the issue is bullying. I think, also, that you are pretty unreasonable yourself there - he's not making things deliberately as hard as possible. Nobody told the Debian guys to standardize on systemd.
It's not purely technical. Pottering absolutely has attempted to force adoption, if not directly with the distros then with the gnome integration. Systemd has succeeded where technically better alternatives failed by encouraging downstream software to hard-depend on systemd, rather than offering/conforming to a standardized interface, which is a dirty tactic, user-hostile and technically damaging. And the refusal to accept patches to add support to non-linux systems to systemd is technically indefensible and completely antithetical to the spirit of open source.
Lennart didn't force anything on GNOME, please stop these false claims.
The GNOME developers simply had two choices: keep using the old, bug-ridden and still-unmaintained ConsoleKit or switch to the simpler, more powerful logind D-Bus interface.
ConsoleKit is still more-or-less supported upstream, but given it's extreme bugginess many distro choose to disable it and rely on logind interfaces.
Note that this does not mean that GNOME depends on systemd: as long as something else is implementing the needed logind interfaces (eg. systemd-shims) GNOME will happily run.
And no, a maintainer refusing patches is absolutely not "antithetical to the spirit of open source". The spirit of open source is that you can fork if you don't agree with a maintainer. It's simple as that.