It's ironic that now, when anyone can publish their writing to the world in a blog, so many people don't have the writing skills to communicate effectively.
Also, it's always been true that many people don't have the writing skills to communicate effectively. What's different today is that for the first time, those people have the ability to publish their writing.
Unlike a printing press or a broadcast frequency, the internet is unbounded and access is dirt cheap. There's effectively no cost to publish crap, so there's no reason not to wait until after publication to filter for quality.