You received a response. What if you hadn't? How many hours did you invest? How many of these would you be willing to attempt if you never got a response of any kind? When the author speaks of abuse, I believe -- in part -- this is what they're trying to highlight. For every submissions, like yours, that gets a response, there are probably hundreds that hear absolutely nothing.

I'm OK, within reason, with these homework assignments if they come after some kind of initial screening where the company has shown at least the minimum level of interest.

However, as the very first step, it feels off to me.