The Democratic Party is trying to gobble up more of the economy to spend through the federal government, the Republican Party is trying to make it eat less. How are they not left and right?
And under George W. Bush the Republican party created the Department of Homeland Security, the purpose of which is arguably to "gobble up more of the economy to spend through the federal government." And engaged in new excesses of deficit spending (since exceeded by Obama, true).
The broader point is that politics is multidimensional. It's not just one axis. The history of tech policy votes in Congress is a good example that's close to HN home.
You can't map being right and left wing to a scale measured by "desired percentage of GDP to be spent by the government." Consider: Bush or Clinton? Huckabee or Romney? FDR or Hitler? Ukrainian anarchists or Stalin? French monarchists or Jacobins? Southern segregationists or Northern industrialists?