We are total agreement. You do not have to register to protect your copyright, but you do have to register to sue. No disagreement. How is this article misleading?

The key point is that if you register ahead of time, you get much stronger protection under the law including the ability to sue for statutory damages instead of actual damages. That can very well be the difference between being able to afford to sue and not being able to afford to sue (or finding a lawyer who will take the case). Note that this point is specific to the US.

There’s a reason that every major media company (music, movies, etc) registers all their publications. It’s well worth the money and that is the message I’m trying to spread to professional-level photographers.

If you are just publishing some photos online for fun and don’t care to ever sell them for money, then this is all a moot point. In that case, registration is probably overkill.

Here’s a good primer.