The argument on the other side is that this is a matter of what's good for society in the long-term. For example, supporting a law that says "let's take all the

The argument on the other side is that this is a matter of what's good for society in the long-term. For example, supporting a law that says "let's take all the money of class X and give it to the rest" would always be "in the interest" of the majority in the short term. That doesn't make it right.