I know you are meaning well, but while the economy growing can be a nice side effect of this (and probably is), I always find it a bit sad when economic profit is used as a reason to justify to create a more fair and equal society.
It's similar with those studies showing hiring a diverse workforce is actually good for your business. It might be, but, like, it's also the right thing to do to not discriminate against minorities.
Unfortunately, this is how some people think, so phrasing things in this manner is a way to win them over ("paying a bit more in taxes is actually going to benefit you").