Hey, author here.

I wrote this back in January and I am aware of what you are saying about people rushing too fast into DNN.

The article is an answer to some people asking me for general references.

But I agree with the disclaimer in general and will incorporate it into the article.

BTW, I started with Ng's course simply because of the way he teaches in a very clear way, and not scaring people out, it is a very good intro and most people would feel confident in moving forward to other resources after his course.