Making (forcing) us to flush with gray water doesn't bring those without clean drinking water any closer to that reality.

In addition, is flushing with clean, sanitary, water a problem? Is it a health risk? If it doesn't make one difference or another, why do it? Is there truly 'no burden' in actually converting to a dual water system? If so, why are we not doing it now? (I'm certain if we followed this argument it would eventually end in the Godwin-like Big Oil barrier).
I never mentioned forcing, I said incentivising. That said it would, of course, be your tax dollars paying for the incentives.

Yes there is a burden in converting to a dual water system: The one time cost to set it up. The benefit will be a hugely decreased cost to deliver your water on an ongoing basis. Sanitising water has a high energy cost, both in financial and enviromental terms. I'm willing to bet you don't care about the latter but hopefully the former might get your attention. Further, we're reaching the point where sanitising water isn't producing enough volume and we're start to de-salinate sea water instead. That has a HUGE cost.

Ultimately, whether it's worth doing or not depends obn whether the benefit outweighs the cost. I'm willing to bet that the need to de-salinate will be the tipping point on that equation.

Just to clear up another miss-understanding. America adopting grey water won't directly help any children in Africa get clean drinking water. The benefit is in reduced costs and lessened enviromental impact. It could probably be argued the lessened enviromantal impact would indirectly help deliver clean water to Africa but it's almost impossible to prove.