She has some creds...
Those idiot and dummy books often provide a compilation of known and somewhat undisputed information for people to get acquainted with the issues. They tend to not be hard core detail or advanced concepts. Authors are merely assembling the basics. While it takes some effort and know how on the part of the author, they are not breaking new ground. But their work is often useful to beginners.
The "retirement is boring" article... She is probably freelancing and needed a topic. It is an eye catching headline for the article to draw people in.
What she said is general advice. However, boredom is not the primary issue. She gets at the primary issue a couple of paragraphs into the article. Obviously if one has not already figured that part out, there will likely be problems (for many).
Next try living on the income you will have coming in as a retiree. Calculate what your sources of income will be and try living on that for 3 to 6 months. How tight is it? Can you still do the fun things you had planned? Will you need a part time job in retirement? Do you need to work longer and accumulate more benefits?
IMO - the problem is the word "RETIREMENT". I prefer the words Financially Independent. People who stop working should have some sort of interests to fill their day. I think most people can deal with it quite well.
I cannot speak for the rest of the world, but I can for myself. I have many personal interests to pursue. They are things that I wanted to do earlier in life but for one reason or another it was not practical.
Now I get to pursue those things! I am sure I will pick up quite a few more goals along the way.