The difference between manipulation and influencing is whether or not something underhanded has occurred. You can sell yourself while being totally honest.
So many things in business are sales transactions, and it's better to come to peace with that early on. Sure, we're engineers but if you want your value to be recognized you have to learn to be a businessperson too.
Indeed, and the fact that unskilled engineers with good business skills can and always climb to the top proves my point : those success stories happen because the kid is a good salesman not because he taught himself software engineering.
This does not prove you can make money by learning some wordpress overnight but still the article pretends exactly that. The average worker with average sales talent will have to present real skills to an employer to get hired. Those real skills take time to develop. It's evidently possible to get them outside of Uni but it takes times and effort. Guidance by experienced people reduce time and effort to learn a skill. That's the whole point of schooling btw.
Those article say "I taught myself how to code and became rich by offering the world an awesome product". They should be "I'm a very good salesman and I became rich by getting people into buying my software".
That software is maybe good, maybe not. Mostly not. Second law of thermodynamics teaches us that you can't beat a 30 year old experience with an overnight schooling, except if your father is zeus or someone like that.
It's not manipulation. It's always a sales proposition, but you're either doing it well or you're doing it poorly.
Obviously, there is no external, impartial arbiter of what makes a "good" programmer (or products, or services). There is only perception.
I used to drift around but I've learned the importance of selling myself so I can be sure I get the value I deserve.