Summary: the warrant to gank Chen's equipment should not have been issued to begin with.
The article says that "Federal and California law both protect reporters against police searches aimed at uncovering confidential sources or seizing other information developed during newsgathering activities." The commentary discusses the author's opinion that Chen's equipment should not have been taken under sections of the Federal Privacy Protection Act and the California constitution designed to protect journalists. The article does not discuss whether Chen would be a journalist under those laws though it appears to tacitly assume that he would be.
However I can't find a link to back it up so..
It does say that the CEO cares more about breaking the story first than verifying facts and sources--but I don't see where he goes so far as to state or imply that he doesn't consider Gawker to be journalism. And he is quoted as saying: "We may inadvertently do good. We may inadvertently commit journalism. That is not the institutional intention." I can see how that might mean what positr0n says but I can also see how that could have a nuanced meaning in the context of the WP article.
A link posted on HN the other day noted that, in the state of New Jersey, bloggers aren't considered journalists. Depending on context, editors may or may not be considered journalists. I don't know the relevant California state laws or court decisions.