I would be very careful with financial advice in general and "set and forget" strategies are definitely among them. There is some controversy with ETF based allocation strategies (see Michael Burry's recent claims) that may or may not be valid, but in general I don't think there is any shortcut for financial education such as "just buy diversified ETFs" (and this applies to many other fields as well).
I don't know, for people who neither have the time, skill or will to invest individual companies' performance a low-cost, very broad ETF is pretty universally excepted as your best bet.
I agree; one should educate oneself. That's why my advice was to "learn how and why" rather than to simply do it. The danger with the financial sector is that there is a ton of biased, bad advice out there. So you need to take some care and critically evaluate what you're learning. Having done that myself, I'm a strong believer in low-cost, diversified investing. (Which usually means passive indexes, but the important things are low cost and diversification; occasionally that's not incompatible with active funds.) For most people who don't want personal finance as a hobby, an hour should be enough time to learn why a simple portfolio of low-cost index funds is a solid choice, and then they can confidently stay the course, rather than trying to time the market or pick winners and ending up worse off for it, as many do.
That doesn't change anything. 12 years ago I knew nothing about programming. Does that mean I shouldn't start with some easy language that might turn out not be sufficient as I get more experienced? No. Starting is the hardest part, gaining experience is something that happens during the journey.
