Philadelphia’s outlandish soda tax is what Democratic-party politics looks like when it lets its freak flag fly. So many classic elements are there: (failed) social engineering and “think of the children!” on one side, paid for with a punitive tax on poor people and destroyed businesses, which means destroyed jobs, which in turn means lives upended. What lives? Greedy capitalists with monocles, maybe? No, they’ll be fine. Think of ex-cons trying to regain their footing in society. To review this debacle, in 2017 Philadelphia, seeking to fund a universal pre-K program, slapped mammoth sin taxes on Coke and Pepsi (and...