> Maybe they are written by non-parents or their children are much easier
To be frank, the article tips are pretty sound and well-accepted, including from specialists who deal with much more difficult children then you and me on a daily basis.
First point, there's a tendency to see one's kids as special, be it especially gifted, or difficult, or an astonishing critical thinker for their age. It's quite understandable, since we have an infinitely deeper relationship with them than with any other kid. Secondly, it's much more difficult to deal with relationship issues when you are involved in them; that explains why you can often clearly see what's wrong in others' relationships (parent/kids or S.O.), but yours always seem more complicated by several order of magnitude. And thirdly, we can also find it quite irritating to be given some basic tips when we are experiencing hell and we feel like we are so past that kind of "pop psych". It's like, "Do you think we've not tried that already?".
Of course, a few tips are no magic bullet (sorry for the cliché), and sometimes the problems are just too serious, but on the whole they just deliver, to the surprise of many parents when they see it used successfully by specialists. I'm not one of them but I know a few, and I personnally use the "give them a choice" tip and if done correctly, I have found it to work very, very well--for parenting and in life in general.