I don't necessarily mean this as a counterpoint, but more as an addition? Working from a photograph is a good exercise for improving technical skills—more as a means to practice with a medium than anything else. Of course it's better to work from life/with your own content, but I don't think you necessarily need to discount copying photos in their entirety. It's a tool similar to tracing—something that can be helpful when used correctly, in moderation, and more for studies/exercises than finished pieces. I mean, you mention craftsmanship, and sometimes that's all you want to work on improving at the moment.
But I largely agree with you, I think. If you want to learn anatomy and form through photos, you're putting yourself at a severe disadvantage. On the other hand, I understand that sometimes photos are all you can access, which can be frustrating, but work with what you can.
Either way, it's definitely best to credit photographers.