It is possible to construct examples where they are connected like that.

The topic at hand is not one of them.

To prove that, you need to show something like that the loans turned out to have been made profitably on net in the long-term after adjusting for risk and opportunity cost etc.

I'm not sure thats true, I think what you would want to show is that the loans 'forced' on the community banks are at-least-as-profitable as the loans the banks voluntarily took on. Given the bizarre financial period we just lived through, the losses on loans is going to be markedly higher across all institutions.

Maybe the next decade of CRA type lending won't be contaminated by massive changes in the financial sector and a large crash- in which case maybe the questions of discrimination will become easier to untangle. For the last decade, the housing market underwent major changes, and the community banks were such a negligible sliver of the overall market that the CRAs effects are on community banks are higher order corrections to higher order corrections.