There are many other mistakes. The author also says "Fifty years ago Medicare and Medicaid didn't even exist, and federal spending on other health-related services made up a tiny sliver of the whole"
This alone represents a false 20% reduction to the "Defense" budget, at the expense of increasing the appearance of social services budgets. If one adds up all defense related spending not by Federally published categories but by actual expenditures then the picture changes radically -- and it looks a lot closer to the budgets of yesteryear.
"Federal spending has grown roughly as fast as the overall economy over the past 50 years."
And then immediately after that says spending climbed from 18% of GDP to 24% of GDP, which is a 33% increase.