Or, maybe you're missing the trick and people have to mind their own dollars so closely when they are effectively punished by the government for giving it away by still being taxed for it. It's their money, after all, not the government's.
It's also an axiom of public policy, that anything you tax you will get less of it. It's the putative reason for taxing cigarettes, for example, to discourage smoking them. In the case of charity -- if you tax the dollars that people would otherwise donate to worthy causes, there will be less of those dollars donated.
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What pretense? Objective facts not subject to rational disagreement are hardly pretense.