It's the BSD approach that's divergent. /usr/local is supposed to belong to programs that have been manually installed by the administrator. BSD's awkward and frankly unhelpful split between packages and ports means they need one more level of hierarchy than linux (rather than package-managed programs and manually installed programs, you have package-managed programs, ports-managed programs and manually installed programs); unfortunately they've taken over /usr/local for the ports-managed programs, leaving you with nowhere for manually installed programs. And while ports purports to support a configuration variable for changing where ports software gets installed to, it must not get tested because a number of programs break if you try and actually use it.