Engineering isn't about "you cannot do that", or "that's wrong". Engineering is about knowing why you cannot do it so you know when / where you can do it.
People holding a simplistic view just lack common sense to understand that.
You know dhenry that is probably one of the few bits of wisdom from you that I can agree with. But even then such wisdom when responding to beginners to electronics is bound to do more harm the good. Too much cargo electronics going around these days as it is.
Lefty