Spending money to try and stop homes from being built in the midst of a severe housing shortage is, to put it bluntly, gross.
The infrastructure is just an excuse. The roads they're talking about are some of the least busy in town.
Also you're never going to "just one more lane, bro" your way out of traffic. You need:
* To put more things people need day to day closer to where they live, so they can walk, bike, or still drive, just not so far. Zoning prevents this in much of the US.
* To build alternatives for the people who are able to use them, like bike infrastructure, transit and so on.
But you have to start somewhere, and you can't wait until everything is 'just right' before you build homes. The real world doesn't line up like that, it works in fits and starts and you do what you can where you can.