Because he is an observer of hacker culture but writes as if he is a participant.

He's definitely a participant, both in terms of software (off the top of my head: fetchmail, several contributions to Linux, Emacs, and Nethack) and tech books (The Art of Unix Programming, some of Learning GNU Emacs, others).

If anything, the problem with ESR is that he considers himself an expert on explaining hacker culture to outsiders, yet tends to excessively project his own values, politics, etc. on it when doing so.

Perhaps instead of "a participant" I should have said "as if he is representative of hackers" which manifestly he isn't.

Now excuse me, I'm going to play my flute for a bit, then go and shoot something, and maybe write some more of my sex-advice column :-P

The concept that any one individual could be representative of hackers is fallacious, and neither does ESR purport to be representative of hackers, even though many of his views and his style of reasoning are indeed common amongst hackers.

Agree 100%

Now, I do find that his values and politics and opinions are rather typical of hackers . . .

While he has deleted my comments on his blog (and arbitrarily and unfairly so in my opinion) and is not the nicest person, he is quite generous with his time and energy - I have learned a lot from his writing. As a matter of fact, it was through his writing that I found PG, and many, many other sources of enriching, life-changing information - I have a lot to thank him for.

Update: it appears that the spam filter on ESR's WordPress installation is what deleted my comments on his blog.

How has he not participated?

I believe that he is indeed a participant.

His work speaks for itself.

Now, his personality might be a bit abrasive to some (to say the least) yet - as I have stated on /. before - let the first geek/nerd/techie/hacker with the all around pleasant personality cast the first stone.