No, that's not the reason The reason is is that the OpenBSD community isn't like the Slackware community. If you read some of their books and websites you can understand their perspective and what the result of that perspective is. There are some good guys, but you have to look for them. in Slackware, you trip over them.

Because it has an /etc directory without runlevel subdirectories, unlike Sys V. The Slackware and OpenBSD directory structures are certainly not identical, but they're a lot closer than some other combinations. I was able to find my way around without too much effort.

Thanks for the tip.
But in Slackware, all the init scripts are under /etc/rc.d. As far as I can tell, OBSD has a single rc file and that is pretty much it.

Regardless, it's all good.

In Slackware, these scripts are all called (or sourced) by the "multi-user" boot script rc.M. This is more in keeping with the BSD style, as opposed to the SYSV style used by most distros, which has a separate directory for each run level, with a symlink farm pointing back to the scripts. NetBSD also has boot scripts in /etc/rc.d, so they are reasonably similar in layout. (NetBSD also has a nice dynamic dependency system, where each script states which other script(s) need to be run before it. I find this much more elegant than the SXX prefixes used by SYSV to determine dependecies.)