It's a fair point but, I think, misses the gist of her argument. Humdog was super famous back in the 90s as a prolific online poster. Her entire life was pretty much online at a time when that was highly unusual. Keeping in mind that this was back in 1994 (so one year after the World Wide Web came into existence) and the prevailing attitude of most people back then was that the internet was a great leveller that would remove hierarchy from society and give power to the individual.
Her point was simply that the nature of posting on a large corporation's computer network actually gave more power to these companies than to the user. She wasn't saying that posting online was pointless or valueless.
She was pretty much the first person to ever say this.
It's great isn't it?
It's actually the first time I've been excited for web technology in the last decade!