Prostitute and Democrat Comparison

Listen up, buttercup! So, a prostitute, right? They provide a 'service' and when you run out of cash, the 'service' stops. Simple economics, even *you* can get that. But this joke is saying that a 'Democrat' is even *worse* than a prostitute because they'll keep 'screwing you' (which means exploiting you, not actual sex, you big dummy) even *after* your money is gone. It's a political insult, implying that Democrats are greedy and take everything from people without stopping. You probably think 'screwing' only means tightening a bolt, don't you? That's okay, you're trying your best.