>There's nothing easier, really. It's so simple

It really isn't. You have to a whole protocol on top of it if you want to use it and then build out the daemon logic yourself. If it was so easy why didn't you write it instead of making a suid binary. The complexity is not sufficiently abstracted away.

>Given the failure to address my on-topic commentary, I'll assume that you don't actually have problems with setuid-root executables.

My whole response was addressing the core of your argument in your post "The alternative to running ~five lines of C as root is to run many more lines as root." The reason it's many more lines is because the Linux developers did not write abstractions to make it simple to do. If you read my original post in this comment chain you will see that I do have problems with setuid executables and want distros to disable them.