That depends on what you have to say, and on what your goals are.
If what you say is controversial enough, you could make more enemies than friends. Alternatively, you could just expose that what you have to say is worthless garbage, or that you're an idiot. (I'm not referring to you personally, of course, just to writers in general)
Of course, some believe bad publicity is better than no publicity, but I'm not so sure that's true.
It is better to remain silent and be thought a fool,
than to open your mouth and remove all doubt.
-- George Eliot
If a young writer can refrain from writing,
he shouldn't hesitate to do so.
-- André Gide
I occasionally play works by contemporary composers,
and for two reasons. First, to discourage the composer
from writing any more, and secondly to remind myself
how much I appreciate Beethoven.
-- Jascha Heifetz
I think the kinds of things you are quoting are archaic. They belong to a world of books, where people write four or ten or at twenty books in a career, and each one is precious and carries with it much reputation. I don't see the same thing with blogging at all.
Even if it was, so what? If you're young and make mistakes, who cares? Are you afraid that some day, someone will say "He's an experienced guy, but when he was nineteen he wrote a piece of garbage?" Self-censoring because you are an idiot or inexperienced makes no sense whatsoever: If you don't trust yourself to speak, how do you trust yourself to know whether what you have to say is interesting?
Reputation is asymmetrical. People start companies and fail many times, but one success makes a career. While I was writing garbage in 2004, people told me that I had no idea what I was talking about, and then one day in 2005 I wrote a rant called "What I've Learned From Failure," and immediately everyone forgot the garbage.
Should I really have waited a year to write that? How would I know to write that piece but not to write "Are you a perfectionist?," which I wrote the week before? How would I know to write that one but not "Passionate Communication," which I wrote the following week?
There might not be an obvious, direct penalty, like someone charging you money for every essay that wastes their time or which they find insultingly stupid. But there could be indirect penalties, such as a potential employer reading and disliking what you wrote and not offering you a job based on it. There could be other social penalties as well. And it's not like the people who snub you because of what you wrote are necessarily going to tell you that your writing was the cause. You might never know; but that doesn't mean there was no penalty.
"I think the kinds of things you are quoting are archaic. They belong to a world of books, where people write four or ten or at twenty books in a career, and each one is precious and carries with it much reputation."
What you write on the internet could have a much larger impact on your reputation than what one used to be able to get away with in the print world. It used to be that if you wrote something that sucked and yet still somehow managed to get it published, it wouldn't sell much, and it would be forgotten. Now whatever you write (on the internet especially, but also in print) may never be forgotten, and could haunt you for the rest of your life. So the potential consequences for yourself are quite a bit more severe than they were when those quotes were written.
The other thing to consider is your reader, and the harm you do to them by publishing crap. You could be wasting a lot of people's times, if they actually read it. (Again, I'm using "you" in the general sense, not you in particular. For all I know, your writing could be marvelous) There's already a ton of garbage published, and more garbage is published every day. Do you really need to contribute to the tidal wave of crap?
Now, there's a difference between writing a lot for yourself, stuff that no one else would ever see, and things that you actually publish. Writing a lot in private could at least make you a better writer. But it might be a good idea to be a bit more selective about what you actually publish. There's something to be said for publishing just the gems, rather than everything and anything that happens to come out of your mouth.
So I agree there is a potential cost, and if it's too high for you, I respect your position even if I don't follow your strategy.
The other bits of strategy you espouse would not work for me personally. If I write privately, I don't get any feedback. For example, let's start with the assumption that this essay is terrible advice. How would I know that if you didn't read it and tell me so? How would I know that the extra length looks like malicious SEO optimization if some nice person elsewhere didn't accuse me of trying to manipulate Google?
Only by publishing my writing do I get the feedback I need to improve. And I get it immediately, no delay, and with no sugar-coating or tactfulness that might come from circulating my writing to a trusted group of friends.
Also, you say only release the gems. How would I know what is a gem and what is not? I don't want to bore you with more examples, but many of the essays people have thanked me for writing were ones I didn't think would go anywhere. Were I only releasing the ones I thought were gems, I'd never have written them.
Now as to harming the reader. I take the position that HN takes care of that. If I write something and it dies on the new page, only a few people wasted their time. I'm not suggesting that there be no filter on my writing, I'm suggesting that aggregators like HN are the filter.
Compare and contrast this to the situation a few years back, when people used RSS feeds. In that case, all of my subscribers would probably read everything I write. Yes, after a while they would drop my feed if I was wasting their time. But today... I don't even offer an RSS feed or a consistent source of my writing.
If people like it, it gets around. If not, it doesn't waste that much time because it doesn't get the upvotes or the retweets to do much damage.
I can answer the question of whether my writing is marvellous. It isn't. At best, it follows Sturgeon's Revelation: 90% of it is crap. My argument is that publishing 90% crap is working for me, although I can appreciate the argument that either it isn't really working for me or that it isn't a good idea for someone else to blindly copy my strategy.