Let's be blunt: Sturgeon's Law applies. Many coders are lazy and half-assed. They take little pride in their work.

This is why you see so many little aborted projects where someone lost interest after the first weekend of work. This is why you see defensive coders complaining about how people expect their "active" project to ever update again. For many of them, there's not much interest in offering a useful tool or collaborating to create better software; they just want the egoboo of saying they made a "project" out of some slapped-together code that never really needed to be in a public repository.

I write open source software for fun. No other reason. Your ability to use my software for stuff is a side benefit for you of this. Writing documentation is not fun. I don't want to fill my fun time with not fun activity. I will however take money for writing documentation (quality not guaranteed).

But I don't use your software. I use software written to be used. Web.py is written to be used. The developers want people to find it useful. Lighttpd is written to be used. Apache's software is written to be used. Ruby and Python are written to be used. Perl is written to be used. Yes, they may all be fun for the developers, but ultimately, they strive to be useful. I'm sure not every aspect of developing a major open source project like one of these is fun. I don't know anyone who finds debugging fun, for example. It has to be done though if you want to produce something useful (even if only to yourself). Documentation really should be done if you want to produce something useful to someone other than yourself... and even to yourself if there's any chance you'll leave it alone for years and then pick it up again.

You make a good point, however:

1. I have had many people become angry with my stance on documentation for MY projects (written with the above contraints, for fun, for me, if you want to use it: cool not my goal tho). That sort of entitlement ruins it for everyone.

2. It is still done for free, if you don't like the results offer compensation for your choice of improvement. If the work is all volunteer, some stuff that isn't fun won't be done. (debugging is more fun than documenting, since the former is required for something to work right). This is why most non-profits also include someone who is either paid or otherwise rewarded for doing the crap work.

Even bad writing isn't really very easy. And bad documentation can make the situation worse. Why would anyone want to do that?