The threat of burning cities has been an excuse for inaction since 1965.
Had the earliest "burners" been promptly crushed, we would not be worrying about this possibility today.
You should read Jefferson’s warning what may happen when the slaves are freed and are colonized.
Jefferson the Virginian, Dumas Malone page 266:
The paragraph begins..”Deep rooted prejudices entertained by the whites; ten thousand recollections, by the blacks, of the injuries they have sustained; new provocations; the real distinction which nature has made; and many other circumstances will divide us into parties, and produce convulsions, which will probably end but in the extermination of one or the other race.”