> So food is really important and vital. Should the government be in charge of growing and distributing food?

> Of course not. This experiment has been tried with horribly deadly results.

I assume you're referencing famines in communist countries, etc. In those instances, the government had a monopoly on food growth and distribution.

Your example is irrelevant because the USPS is just one of numerous mail carriers (UPS, FedEx, etc).