As I said in my comment, "That is, living with parents after graduation is done to just survive, rather than to save more and pay off student loans faster."

My problem is that the advantages/payoffs (more savings, faster student loan payoffs, etc) of sensible/smart behavior are removed, while the misery/discomfort/etc (living with parents, being looked at funny, not being able to be alone) remain (or are made worse).

It's even worse if the idiots then repeatedly bring up the advantages (to excuse themselves of what they did and to make it seem there's nothing wrong with what they are doing), as though they still exist.

You seem to have strongly internalized the notion that only 'losers' live with their parents, and hence it's inherently wrong to do so. I would question that assumption.

It's the US that's the outlier here -- in most countries, living with parents at least for some points in time is the normal thing to do, for the simple reason that it's more economical.

In China it is normal to live with your parents (and even grandparents) all your life -- even after marriage and kids -- so that you can take care of your elders.

Due to the land allotments in Cuba, this is actually very common. Big houses (5-6 rooms) with three generations or four are not uncommon.

What makes you think I've internalized such a thing?

The stereotype is that losers live with their parents. It was fairly common for smarter new grads to live with their parents (to save more money). These days, it seems almost mandatory in many cases, especially if they can't find a job.

That said, even with it being obvious what's going on, the idiots can't resist saying the dumbest thing. But that's them in general: no matter what's going, they are always looking for a way to say something stupid.

As for me, I'm 30 and living with my mother, but I'd definitely rather not be. I'm not living with her to be smarter, it's because I'm unemployed and unable to function due to mental illness (though as I said above, I think someone is did this to me).

If you are being cheap because you are willing to sacrifice now to make your future better, that's one thing.

If your obligations are such that you have to accept samewise conditions just to eek out an existence, it's entirely another thing.

If you choose to live on a dollar a day because you temporarily rely on your family to provide certain externalities, that's one thing.

If you have a dollar to spend per day and spending it poorly means you go hungry, that's quite another.

What would living on a dollar a day entail in the US ?

Unless you would happen to qualify for public assistance, you'd be nearly starving and exposed to the elements. You simply can't meet basic needs on your own with that without outside support. There are a few exceptions for temporary circumstances (You might be able to farm and live in your paid-off house, for example, but without utilities - and you'd be out of luck when your first property tax bill arrives).

cardboard box and a cheeseburger for lunch (dumpster diving for dinner)

It happens on a 20 year lag, so by the time it becomes the norm, it isn't necessarily any of those things.

Similarly, micro versus macro economics: we can end up in a globally bad situation from everyone making locally good changes.

People become risk averse.