USA explicitly targeted people, civilians, & city per se when attacking Hiroshima w/nuclear weapons. Public & gov efforts to cast Hiroshima as primarily, and selected as, a military target were justifications & PR. Targeting people means you destroy stuff near them like hospitals.
There were 76,000 buildings in Hiroshima at the time of the attack: 70,000 (92 percent) were damaged or destroyed, 48,000 of them (63 percent) completely. As a Japanese assessment later reported, βIt is no exaggeration to say that the whole city was ruined instantaneously.β