All those portability claims and that there somehow good: you're just doing things for lowest common denominator. Requiring a huge amount of effort to change or develop low level bits across BSD and Linux.
Now systemd comes along and does a lot of things for us. While you'd still have dbus. We now have people who solely developed for Linux and they're installing FreeBSD, that's indicative on how much development resources there are on BSD!
You imply that GNOME developers (none running or knowing anything other than Linux) are bad because they're not also developers for BSD. I've seen other people claim that us focussing mainly on Linux will somehow reduce the amount of help we get from BSD and so on. Yet practically speaking, the amount of developer resource we received during most of GNOME 2.x from BSD is pretty low (mainly implementations; hal, upower backends, etc). Plus often lagged behind a bit.
Recently we're making clear that we focus on Linux. We're still as open to portability as before, but someone really has to put in an effort to do this. Putting that with people who have only used Linux and mainly care for Linux is a bit strange IMO, especially after all those years.
Given that *BSD often did lag behind and did eventually provide implementations, the situation has not changed much. Expect for the often repeated claim of "forcing things".