Approximately zero programs will call all of those functions, but each will call its own required subset of them. If you don't care about running the child with an altered root directory, you don't need to call chroot().
I don't think anyone who's thought about it for a moment disagrees that starting a process has a large degree of potential complexity, regardless of the operating system.
The question is whether it's better (more elegant) to load that complexity onto one complex function call, or farm it out to multiple simple function calls. It is apparent that this is a question in which personal taste is involved.
