"umm because if they'd been taxed a bit more along the way and spent it on social programs, people born to less advantaged families wouldn't be so likely to follow their parents down the road of poverty. social mobility has huge economic benefits in terms of optimal allocation of means of production....
And you aren't giving money to poor people directly, you're doing it through healthcare, education etc. that have social returns (positive externalities) while still bringing considerable economic benefits. "

Are you not trying to convey your thoughts on redistribution of wealth through the gubment? Because if you aren't, I believe you are a little confused about how taxes work partner. Taxpayers do not allocate taxes, the government does. The multiplier relates government spending to output and employment. So it sort of has everything to do with what you are talking about. Also I never said the multiplier would debunk anything. I said if you were a Keynesiast and actually knew about economics, that would be the theory that you would try to use. Personally I think it's garbage but then again I think Keynesian economists are fools. I was just trying to figure out what school of thought you believed in.

And you are absolutely right when you say "Government investment doesn't necessarily have a higher multiplier than private investment" Again this is why Keynesian believers are fools. Redistribution through the government will destroy an economy faster than a politician breaks a promise. Redistribution in a healthy economy will stem from ingenuity and innovation. That's a fact brother.