I mean I paid for it like I would anything else I wanted. They charge a tax at checkout. So if I buy a house and pay the whole thing off, why do I still have to pay taxes on said house when I paid the whole agreed on price in full? It would be like me buying a six pack of beer I pay for it and tax at checkout. But then timely I have to keep paying taxes on the beer even though paid in full?
Housing taxes provide money for local governments to provide services like local roads, garbage disposal, water and waste services. Things that are generally required to make an area livable. Those are ongoing expenses unlike the beer you purchased.
Taxes on goods generally go to the state to provide state based services and supplement local governments.