Not the OP but here's an example.

And yet conventional ideas of professionalism have such an iron grip on our minds that even startup founders are affected by them. In our startup, when outsiders came to visit we tried hard to seem "professional." We'd clean up our offices, wear better clothes, try to arrange that a lot of people were there during conventional office hours. In fact, programming didn't get done by well-dressed people at clean desks during office hours. It got done by badly dressed people (I was notorious for programmming wearing just a towel) in offices strewn with junk at 2 in the morning. But no visitor would understand that. Not even investors, who are supposed to be able to recognize real productivity when they see it. Even we were affected by the conventional wisdom.

http://www.paulgraham.com/foundersatwork.html

The idea being, in that ultra-early-stage, 2-3 founding members only, state, trying too hard to be "professional" is counterproductive. Obviously, at the scale that we're talking about with Github, the game changes.

Ah, ok, I agree there's a big difference between an ultra-early-stage startup and a company the size of Github. But the latter criterion is what seems relevant to me for this thread, since it's about what happened at Github.

Unprofessional workplaces-

Limited or no dress code No set hours Limited involvement of HR Wide degree of responsibility -- limited written work descriptions Amorphous groups of collaboration that develop and disband

And on and on. Most technology companies, even once they are larger, try to hold onto those "unprofessional" traits. A strong HR group with heavy controls limit or eradicate the ability for some of the less pleasant behaviours, but they also can completely undermine self-motivation and creativity. It's a delicate balance.

I think there's a key distinction here between "unprofessional" traits that can enhance productivity, vs. unprofessional traits that kill productivity.

I agree that the former are good things and should be preserved where possible. (And not just in technology companies; some time ago I remember reading about a study that looked at various heavy industrial companies--auto manufacturers were one type--and found that the most productive ones were the ones that had many of the things you cite: limited or no dress code, limited HR involvement, limited written work descriptions and a lot of autonomy given to workers.)

However, the Github case appears to be an example of the latter. I don't think that's something to be celebrated.