Out of the 2 Android phones that I have had, zero of them came with Facebook preinstalled. I blame the mobile phone provider.
Your blame is at least partially misplaced. Manufacturers also bundle software, regardless of the carrier. The last two Android phones I had were bought directly from the manufacturer as never-locked phones (not to be confused with unlocked, which means the carrier lock has been removed). Yet there still was plenty of bundled and uninstallable software, including Facebook, Twitter, Google+, Drive, Hangout and Picasa apps and integration for pretty much everything. I have disabled more than 20 bundled apps.
The manufacturer assumes that everyone uses the big social media sites and want to tell their friends (and their friends) about everything they do, including what music (or audio books) they play, what pictures they take, and where they currently are.
It's good that social exhibitionism became acceptable (thanks to Jennifer Ringley more than anyone), but that it became the norm to the point that it's bundled is something I strongly object to. It's like buying a toilet and finding out that it (unadvertised) comes with wan connected crotch cams that can't be removed, just temporarily disabled.