Largely, the author doesn't believe that launchd will ever successfully come to BSD. It's had a number of attempts, all of which either failed or fizzled out.
I wouldn't call that a very compelling argument about why nosh is better than launchd. So what if previous attempts to port launchd failed when this port(NextBSD) appears to be working. So far I've seen several people on hacker news say that nosh is a better alternative to launchd, but I haven't seen any specifics, right now it just seems like politics.
Yea not saying I buy that argument either, the compatibility/conversion layers that exist for nosh could probably be built for launchd, so I wouldn't consider those significant advantages. I also wouldn't consider launchd being deployed on OSX that much of an advantage either given that it seems large parts had to be rebuilt to use the BSD kernel interfaces rather than the darwin ones. Maybe that it's already got configurations for a bunch of services for things from Homebrew/MacPorts/Fink, but they would still need to be reviewed for any broken paths and things from OSX that aren't on BSD.
Largely, the author doesn't believe that launchd will ever successfully come to BSD. It's had a number of attempts, all of which either failed or fizzled out.