I'm saying that the argument that most people are doing something is not proof that what they are doing is better.

It's evidence that what they are doing is, or leads to, something being better. And in the cases where it isn't, we can point to a specific mechanism that subverts the general rule (e.g.: addiction).

Personally I would state that this is a false dichotomy and that Rich is better than Poor because it is not-Poor. It isn't necessarily the best state of not-Poor.

You seem to be talking about having a middle amount of money.

Whereas I'm saying a simple thing: for any two amounts of money X, Y where X > Y, all else being equal, is is better to have X (more) and not Y (less). And in particular, it's better to have lots of money (rich) than very little (poor).