Well, they were trying to hit military structures. But they were also aware it was going to hit a fuckton of civilian infrastructure.

They were also trying to end the war faster. The USSR had just joined and were making a lot of demands for Japanese territory immediately. The US wanted to avoid a repeat of the partitioning of Germany by having to give the USSR all of Hokkaido. They also weren't aware that Japan was already at the brink of surrender due to fog of war.

On the grey-er side of things, there was a growing sense of... callousness? Inevitability? on the US's side throughout the war. They started out proclaiming that they would only use precision bombing due to the invention of the Norton bomb sight. Only for that bomb sight to still be fairly inaccurate and had to switch to mass bombing. Eventually the US had escalated to firebombing Japanese cities, and the bombing of Tokyo was on par with the bombing of Hiroshima. The big difference was the span of time and number of planes/bombs involved. If the US hadn't developed the atom bombs then they would have just continued the firebombings with damage to Japan not being all that different.

Add to that the fact that there was a lot of decentralized manufacturing in Japanese cities including military manufacturing. Part of this was cultural, in that it was still normal to have your business be in the same building as your home. Some of this is technical, in that Japan hadn't really invested in assembly-line mass manufacturing yet. And some of this is strategic, in that a small bombing raid isn't able to take out all of your manufacturing, plus there's the factors of using civilians as human shields.

All that said, was there some sense of retaliation and racism against Japan that led to the use of atomic bombs? Yes. Was there also motive to use the bombings to scare the USSR? Also yes. Was a large part of escalation to fire bombing and atomic bombs driven by Curtis LeMay (who was a fucking monster and probably the worst person that Columbus, OH ever produced)? Abso-fucking-lutely and he continued to be a giant problem in the US military well after the war.

Rants aside, my overall point is that the atomic bombings weren't black and white given the context of the entire war. Anyone trying to push otherwise is either (most likely) ignorant or lying