It was certainly useful to me.
That's it. We don't need to project out his intentions any further than that. You're allowed to share your experience and your thought process without it always being some altruistic "save the starving kids in Africa" type message.
The beautiful thing about the internet and the distribution it provides is that you can write content for your niche and actually reach those people fairly easily.
As an extreme example: do you go into Ferrari owner forums and criticize everyone there for being self-congratulatory and living in too much excess? I hope not. Leave them alone and let them have fun with their cars.
Are they self-congratulatory or self-promoting? Or both?
Just from the headline (before I clicked through), I wondered to myself "How hard can it be? Give notice. Be professional during your notice period. Leave." To me, TFA is less about "how to" than "things you might want to consider".