Writing is one of the best ways to learn something. Maybe non-experts learn something by writing about it?

Don't think the entire internet is repeating inaccuracies. :) I also believe there are readers that attempt to learn further than a blog. A blog post can inspire you to learn more about a topic, speaking from personal experience.

If there were no blog posts, maybe there would be no HN I believe.

There should be a place for non-experts. One could remain skeptical when they read blog posts without hating blog posts about complex topics written by non-expert.