This has been discussed ad nauseum. Here's two reasons: 1) look at how many people post to the list with questions about loading libs, how many people post with problems loading single file externals?
there are different ways to handle this ... e.g. a proper #include, import, site-lisp, site-packages, site_perl (i know, this would require changes to the language pd)
ever had trouble with namespace conflicts? Try solving that when you are using libs. Sometimes its not possible.
if i have a zexy.pd_linux and a cyclone.pd_linux, i know, which sources i have, if i have a "prepend.pd_linux" and a "prepend.pd_linux" i have no idea, which prepend i have. splitting libs to externals doesn't really help to solve this problem, it just changes the responsibility from the developer to the user. but it's not helping anything! i think, the only way to solve the name clashes is _communication_ and the ambition to resolve them. but that's a community issue.
t