Part yes, but the poster said that Techcrunch was worthless because of the copyediting mistakes. That's not "part of", that's is.

There's a related idea which says that journalism is good stories and copy editing.

Both are wrong. Good storytelling and copy editing are part of good journalism, but they're not the whole story. In fact, they're not even the majority of the story, even though they're dominant skills of most journalists.