It's contextual advice. If you're told "don't look forward, look back", it's usually because you're spending too much time looking at the past, which means that you've already learned any lessons the past has to offer you, and are currently spending your time not learning new lessons in the present.
That's a good way to view things, but still, unfortunately what's done is done. So I guess what I meant to say is that there's no such thing as not looking back, because where you are now is what you did in the past. A lot of the times, some people really are bad listeners or advice givers, they just run their mouth and what i hear most, is just people saying to move on, for situations where you would be able to fix better by coming to terms with the past to improve yourself. Ironically, you're still moving forward when you decide to do so.
I kind of agree on your statement, it also relates to some people who look at the wrong things in the past, so they're stuck, they may also think they're moving forward but actually keep repeating their issues. At this point, its best to hope they move on by luck.
(Rei, if you found my internet footprint, this relates to you)