Earlier quoted context omitted.
I'd define being 'financially secure', as being confident that you will not need to make changes to your lifestyle for financial reasons. It makes sense that that depends pretty heavily on how expensive your current lifestyle is.
Right. It sounds funny to have a 2x guestimate from many people though. Is that evidence of a common mental heuristic for estimating and mitigating future risk? I personally can think of a net worth figure which seems like it might be comfortable under lucky circumstances (no major crash or catastrophic health issue). And, right now I also feel like twice that would make me feel pretty secure. In spite of my concerns…
The thread starter is ambiguous about whether "secure" means "secure in what you currently temporarily have" vs "secure to have a reasonably acceptable life".