I guess this article is for people who had parents that were generally loving and capable. Parents who were abusive or neglectful are a different matter, and the effects can last a lifetime for their children.
In theory, you're correct that we are responsible for our own issues. But imagine that someone came and dumped a load of rubbish in your garden and left you to clean up their mess - you would probably be very resentful towards that person. Now imagine that I said to you 'it's YOUR garden and YOUR responsibility, so clean it up and stop complaining'.
Sounds pretty clueless doesn't it? That's how the advice in your article comes across.
If you had generally loving parents, then you have no idea what you're talking about.