(It was admirable that Snyder tried hard to push that idea in Sucker Punch.)

Anyway...the quote doesn't really resonate with me. It just sounds too much of a rallying call for the easily impressionable.

I did a quick Google search of who actually said it. And the Quote Investigator website tracked the earliest use of a version of the quote to a 1926 Methodist church announcement: "It is easier to fall for anything than to stand for something."

The Quote Investigator website also lists when other but very similar versions of the quote was used. E.g. 1945 in a radio program called "Town Meeting of the Air", a movie star participant, Irene Dunne, said: "If we don’t stand for something, we’ll fall for anything."

It seems that the quote was used by a lot of churches or those connected to a church.

Here's the Quote Investigator website about the it: [quoteinvestigator.com]

I suppose that must assume that if you don't "believe" in something you haven't given anything much thought. Critical thinkiers will disagree.

its another pile of poop

I believe in all kinds of things, but they need to be real and relevant. Not believing in superstition or make believe is not a sign of ‘disbelief,’ it’s a sign of mental stability and integrity.

The problem with that statement is that if you believe in a total system ideology-- political or religious -- you have already fallen for something bogus.

Disagree.

It's stand for something or fall for anything. Making the stand/fall contrast. I did a little digging and the first appearance may have been during WWII, in the following quote:

We are trying to show him not only what we are fighting against, but what we are fighting for. So many of these boys have only a very hazy idea of the real issues of the war. About all they see is “going back to the good old days.” This is a dangerous state. If they don’t stand for something, they will fall for anything. They need to realize that we are fighting two wars—the war of arms and the war of ideas—that other war of which the war of arms is one phase.

The idea is that you have to have an understanding of an ideal or value to stand for it. If you don't have any grasp of the issues at stake, you can be easily manipulated. So, yes, I agree with it.

It's from a song Aaron Tippin did back in the 80's.

It means nothing and is false. I've never heard it before.

That's a leading question. If you believe something you are more likely to fall for something. As an example I believe in science but much medical and psychological science is based off of poor collaboration = causation. A lot of problems people have had have come from people who 'junk science' vaccination rate dropped because of things that sound scary bringing measles and whooping cough (the 100 day cough, can kill kids who are who get it) back.
There are a lot of scientists that just aren't statisticians/mathematicians. There can be a cult-like trust or distrust of anything that sounds scientific. That goes both ways.

Silly 'trueism' that isn't.