The money the governments are using to pay that contract is generally paid by taxes. So if we go back to the originally OPs point. Those taxes are enforced via

The money the governments are using to pay that contract is generally paid by taxes. So if we go back to the originally OPs point. Those taxes are enforced via force. While not as a direct as forcing a worker to build the house directly. One is still essentially working to build these house in this case. For instance on average 5% income was taxes for this purpose you could treat it as 5% decrease in pay or more cyclically 5% of ones labor is unpaid. However, you can argue this for just about anything the government does with tax money. It's not wrong per se on an item by item basis of government function. Although, ideally government functions benefit everyone in some regard so in practice its not as bleak sounding. Very few people would be hard pressed to receive zero in return from all functions and programs of a government that is not abusive. Although, unless you get one these houses your not getting anything in return here for this hypothetical 5%, again though that is on an item by item basis. There could be tertiary benefits that one gets, but are hard to quantify with a dollar amount if such a program is working well. Such as a more stable community, ect...