The way I've always interpreted it is far more abstract, and probably far more kind, than most people.

It doesn't take a genius to see that there's some fucked up shit happening not only in the world, but in the USA. Most people realize and accept this to differing degrees. Most people will disagree on the specifics of what, even if they might have significant overlap with others.

One thing also almost universally believed is that "things didn't suck so much when I was younger". The reality is that it's a combination of nostalgia, the fact that you were less aware of everything when you were younger, and you had less to worry about when you were younger. But most people can't shake the feeling that things were better when (insert something from earlier in their life).

To me, MAGA preys on that nostalgia for simpler times. It doesn't define what was so great before, when it was so great, or what specifically has changed. Only that something has changed to diminish the greatness, and we have to change it back.

People may not like me saying this, but it has a lot of parallels to Obama's campaign slogan, change. It doesn't define what's wrong, it doesn't define what needs to change, but again it taps into that generally shared concept that things would just be better if something changed. People fill in the blanks themselves with whatever allows them to connect with the concept. The main difference is that "change" as a slogan is not tied to the concept of "going back" to make things better, leaving conceptual room for forward movement.

Ultimately the individual gives both sayings meaning and emotional content themselves, even if they may not be able to explicitly parse it back out to specifics.