What I generally hear is a wealth inequality frame: raise taxes on the rich so that they won’t accumulate savings so fast. Income inequality is much steeper than consumption inequality, and taxes are proposed at the top end of income, not consumption. So it is already sensitive to this concern, and steering clear of reducing personal spending.

Now it’s true that invested savings become goods and services, capital purchases, etc. for the companies you invest in. But the idea is that government will take over some of that role and invest the taxes collected in more socially beneficial activities, with returns accruing to the public.