I’m on board with that, but what feels gross about this is the author does it for fun and gets ripped off by hucksters piggybacking off it for money. And, presumably, much of that stuff is trashy shovelware.
This isn’t an honorable way to make a living.
I agree it's not honorable. But if he wanted to protect what he made he should have at least registered the trademark. By not registering the trademark you're saying that you don't care.
That's more of a grey area. Just because someone doesn't formally file copyright or trademark it doesn't necessarily mean it isn't valid. Same can even go for patents if an invention serves as prior art.