This recommended method (sc. install Ikiwiki using pkgsrc) is not compatible with homebrew and the packages installed via homebrew, and, therefore, not always a viable solution to installing Ikiwiki on Mac computers.
In what way is it "not compatible"? Have you tried it? I can't think of any technical reason why having a working Homebrew installation would prevent one from also having a working pkgsrc installation, or vice versa. (MacPorts and Fink can certainly coexist with each other and with other package managers on the same system.)
We used to direct OS X ikiwiki users to MacPorts, but the version there is almost three years old. pkgsrc's ikiwiki stays up to date because I keep it that way. If someone packages ikiwiki for Homebrew and reliably keeps the package updated, then we could discuss whether pointing folks at Homebrew is better advice than what's currently being given here. In the meantime, if you've tried and failed to install ikiwiki from pkgsrc on OS X, please report your problem in detail so it can be addressed in some way. --schmonz