Why do everyone so casually snuck "child" before "porn"? Are they synonymous?
No, I use the term "child porn" specifically because they are not synonymous. There is a difference between porn and child porn, and as a society we have decided that the latter is illegal and generally a horrific thing, and the people who produce it should be severely punished.
Did you not read the subject matter the article talks about within the first few paragraphs?