If it were due to new facts and information, sure, but a lot of time the "new" principles appear to be self-interest biases manifesting.

Also, if your principles are likely to change quickly, it's probable that they haven't been thought through very thoroughly to begin with. It's not like you have to wait for situations to actually arise to consider them.

In the same way that a scientific theory was meaningless if it failed a test, a principle was meaningless if it needed to be adjusted when actually put to use.

Superseded scientific theories aren’t all “meaningless.” Newton’s laws of motion are superseded, but they aren’t meaningless, and you presumably wouldn’t say that scientists who updated their beliefs in the face of new evidence and explanations were doing anything wrong.

You’re right: “meaningless” was a heavy-handed attempt at continuing the parallel on my part. And sure, they weren’t doing anything wrong, but they fundamentally were wrong in the rules they followed previously. Similarly, if you adjust a principle, you admit that it didn’t hold for you in the first place.

As a tangent: while the parallel to scientific theories is good on the surface, it does lump in this idea that there’s a universal set of correct principles. Isn’t that just philosophy, then? Logical arguments about which principles are sound & universal. Maybe the lesson is to pick principles from the battle-tested ones rather than trying to develop your own.