Overpopulation is a hoax, say the head-in-sand-folks

From a comment thread in an article not about overpopulation:

"Over population is a hoax. You can fit all 6.9 billion in the state of Texas at a lower density rate the 50 most populous cities."

I've seen this trope more than a few times. If you know anyone stupid enough to say this seriously, here's the answer:

"You're right. We'd all fit. Until someone had to use the bathroom, get a drink of water, or eat something. 

"Each person needs 2.5 acres of farmland to have plenty of food, or as little as one acre to live like someone in a poor third world country. Texas has about 130 million acres of farmland. So theoretically it could support 130 million very lean people as long as they all lived in non-farmland areas of Texas (most American suburbs are built on farmland). 

"That leaves you 6,870,000,000 acres short of being able to support the entire human race in Texas."