A link like this exists to give you a one-sided case for using an app. Following that up with a counterpoint seems like the most informative way to proceed. I think the HN standard should be that comments of the form "This would likely improve your product" deserve to be voted up, while "Here's why this won't work" should be voted down.
Most people just aren't very picky.
Sites like this are just throwing away users for no good reason.
Granted, there are "About" and "Privacy" links at the bottom of the page, but a few more sentences might be helpful.
More information is necessary. I'm really scared of signing up to something with my fb account without know exactly what for.
It's not a question of people jerking around the every topic like this, here in hacker news. It's an actual need that those who made the service didn't pay attention to.