But that still doesn't invalidate what GP was saying. They perceive a difficulty in contributing to the conversation because they're afraid of being downvoted. You're telling them not to worry and that they'll be fine ... but it's still a legitimate concern for them and for many other people who lurk and don't participate in the conversation directly. And there are plenty of lurkers. In my limited experience of receiving visitors from HN on my website, the number of clicks is 100x the number of comments on the thread.
And this is exactly why Facebook doesn't have a downvote button. It's trivial to add it. I've even seen it implemented in internal versions. But it only takes a couple of bad experiences of being downvoted for a user to get turned off from the platform. TFA does some handwaving about how it'll save democracy, but it's a crock of shit. All it does is make fewer people participate. crazy_horse tried to tell you that. The solution to saving democracy isn't reducing participation.
What's more, this experiment of having downvotes does exist. It's called reddit. Plenty of people use it. If the author could use examples from reddit to illustrate their point, it'd be great. Like the thriving, polite, constructive exchange of ideas that took place on /r/the_donald for instance?