If you have not noticed, most (90%) of programmers do not work on open-source projects or toy projects hosted on Github. There are great programmers who have never published a single line of code.
Of course I've noticed. One need not be an open-source hacker to have shipped a product, nor, perhaps, need one have shipped a product in order to be worthwhile as a teacher of programmers. One does, however, need to have done something.
His website presents him as a teacher and a motivational speaker. It also includes his claim to be a programmer, substantiation of which is rather thin on the ground. I haven't watched his videos, but if they're anything like his articles, they rarely include code, talk in bland generalities without offering much in implementation detail, and overall read as if written by someone with neither the experience he implicitly claims as a working programmer, nor anything like the level of intellectual capability and flexibility to which he aspires.
Contrast, for example, the whip-smart Steve Yegge on Agile consultants [1] -- which, not coincidentally, is how this Sonmez item appears to make his living, in collaboration with some kind of software-engineering equivalent of Kaplan, Inc. [2]. Pick whatever example you like of Sonmez's writing, and place it alongside whatever example you like of Yegge's, and perhaps you'll find it easier to see why Sonmez forces to my mind the old cliche contrasting do-ers and teachers.
His claim to be a programmer underlies his supposed authority, and his failure to demonstrate any accomplishment in the field undermines his claim; more to the point, if he were any good at it, he'd probably be earning a living by some means less distantly related to the field than selling snake oil to people who don't know any better.
I suggest that you research the idiom, "he may be X, but Y."
If I say "He may be tall, but he's ugly"[1] his height is not in question. Semantically, it means that one of his features may make him effective at something, but another feature (or aspect of the situation) offsets that effectiveness.
> If I say "He may be tall, but he's ugly"[1] his height is not in question.
The idiom may, depending on context, imply acceptance of the proposition that is preceded by "may", but more generally (whether or not that is the case) it means that that proposition's truth is irrelevant, and that the important thing is the subsequent proposition.
Really? He reads like a motivational speaker. What's he shipped? Where's his repo?