I get where your coming from. I think a lot of people find it therapeutic to write some form of journal. It's probably the number one thing any psychiatrist/psychologist will ask a patient to start doing.
That has moved to the web, where everyone has a "journal", only they call em blogs now; and there is no "psychological trouble" requirement to write a blog.
In this case, I think much of the same is happening. An individual is writing in his/her journal. Hundreds of thousands of people do so so every day.
The only difference here is this blogger/journal writer happens to have an audience. I suspect he would have written it anyway, sans the audience, sitting on a failed startup, and without a known name in the industry.
So I see where you are coming from, though I do think it's a lot less calculated or routine or par for the course as you feel.
The only difference here is the audience. Somewhere out there, there is a guy like me, wanting a startup, without a name for himself, who has been through a bit more in regards to some struggles of life/human condition.
Do I blog about it? Yup. Does anyone read it? Nope. Would I continue to blog about it were I a publicly known figure? Perhaps.
Some stuff is private to a point, where I do desire others to read it in hopes it may help them. However, put me in a position of notoriety and my opinion may change.
Right now, I like knowing that those very few who read my stuff don't know me, and I don't know them. It's a nice unspoken agreement of my blog and my position in this field.
Give me success and a little fame, and you may be right; less appropriate a forum to be talking about those things. At the sane time, if that blog post helps only one person gain perspective and get through another single day of personal anguish, all the downsides are irrelevant to me, and I'm sticking with it being a good thing, as it helped one single person get through their own personal hell for that day.
Commiseration can be your best friend in tough times. Just because you happen to have become noteworthy doesn't negate the power and value in knowing you are not alone.
It's funny, we all know how non-unique our situations are. Everyone has been there, or similar. Yet as much as we know that, the second something goes wrong, we feel alone and unique in our situation. Blogs seem to help get our brains out of self pity and loathing and more in tune with the fact none of us are alone, and someone else has been there already, more than likely under worse circumstances. That can be very powerful medicine.