Because sending checks won’t do the job:
I grew up in Detroit. A couple of million dollars to a car company (that borrowed even more tax dollars to “pay their loan back”) isn’t gonna save a city that has more crack houses than able-bodied workers, and more wild dogs than new ideas. Detroit has suffered from half a century of poor leadership, from jerks who bulldozed functioning black neighborhoods in the sixties in favor of project housing, to Coleman Young who spewed so much anti-white hatred at the suburbs they kept moving the borders further and further out, to mid-90s car companies so convinced that gas-guzzling SUVs were the wave of the future that they made deals with union devils that paid 95% pensions and $30 an hour for workers to sleep. Detroit isn’t going to be rescued by hope and change.
An atom bomb that forces the population to scatter and the city to rebuild, maybe, but not an empty suit with platitudes about glowing days ahead. Bears are moving back into the city. You can buy a house for less than it costs to buy a car. In the public school book depository, the books are turning back into trees.
In which case, we may not need the nukes: just let entropy run its course. Same result, lower initial expenditure.