Earlier quoted context omitted.
The argument usually is that by donating your money to a charity that you control instead of paying taxes you effectively undermine democracy.
The majority of federal income tax receipts go to military spending [+] (ignore social security and healthcare, those are funded out of compulsory payroll taxes, which is distinct from federal income tax); you're doing more social good (in general) by diverting wealth to charities that promote social welfare than giving that money to the federal government (I'm sad to say). Sometimes democracy is wrong. More social p…
As a percentage of income tax receipts, the number for military spending is closer to 25%. See, for example, https://www.nationalpriorities.org/interactive-data/taxday/