by 'boots and blood' they mean hard work and dedication. from the first two verses they might be talking about how many homeless people and people on welfare there are in the world that are physically able the work but choose to be lazy and make excuses for why they're like that. and the speaker is telling them to fuck off. they most likely are pissed off bc they sit on their ass and get what they want and we have to work to get what we need.