I don't think that it's a knock on the software, I think it's a knock on the common interpretation of what that software is doing.

Professional photo retouching is art. It's okay to use Gigapixel for an artistic task, it's not OK to use it to enhance a photo that you're going to show to a jury. That's what GP means by 'critical': use cases where it matters whether or not the pixels being added map to an objective reality rather than an algorithmic guess about what would look good.