Dists didn't choose systemd because they had a gun pointed to their heads. They chose it because it is demonstrably better than either sysvinit or upstart.
Funny...I've had no issues on any system running SysV Init Script or Upstart. I've even built my own distros - from scratch - and managed them.
However, I have run into numerous issues with systemd-based distros because of systemd.
Sorry, but many distros are doing it because of not taking the option not to. Debian switched because a couple package maintainers made it a dependency and the Debian maintainers refused to make them make it optional - thus we now have Devuan which maintains that choice. Thus nearly all Debian derived distros don't have a choice but to use it either. (Devuan had a lot of trouble untwining systemd to keep it optional primarily due to the Debian decision not to keep it optional.)
So while there may not have been a gun to their head, it's been an oligarchy that has decided 'systemd is best for everyone' kind of decision when the vast majority don't want it.