I'm all for infrastructure spending. But if when we get to a point where it's like "the overall economy is so productive due to automation, that we can pay essentially the same to have a person go pursue whatever passions they may have, or have them work on an infrastructure project that will get completed whether or not humans are involved," then why force people to dig ditches, just so we can give them "a job."

In the short term, sure. Maybe a jobs guarantee will be good for displaced data entry office worker drones. But if you want to get there by forcing a company to choose a human or efficiency and a huge tax bill, and then using the tax money from the companies that choose efficiency to tell the displaced workers "You can put up these solar panels, or get nothing," then I think you're hurting both the economy and the displaced workers.