I don't think this is about how much money in taxes the state collects. I think the average tax revenue per citizen is higher for the US than for, let's say, Finland (please correct me if I'm wrong). It might be about how this money are distributed to education vs healthcare vs army vs ... But my hunch is that it's not even this, it's about how the system spends the money and not about how much money (for healthcare it's definitely not, as I don't think anyone spends more than the US on average per citizen, but for education I really don't know anything about the figures, that's one of the reason I've asked this...).
There is definitely an issue of how much money is distributed to welfare / infrastructure / education etc compared to military but the lower tax rate means there is less to spend to begin with (per capita at least)
Note that the article says "This article's factual accuracy is disputed. Please help to ensure that disputed statements are reliably sourced." Wikipedia is a really horrible source for topics people may bicker about. In practice, no one pays over 50% of their income in income tax like that article implies.
VAT was also quite high as well (at least in Sweden)