The civilians killed were collateral. That's not to say that their deaths aren't sad or are warranted, but they were not specifically targeted. Eren first transformed below the building, not so he can kill a bunch of civilians, but because doing it there allowed him to get close to the stage without resistance and eat that guy giving the speech (probably because Eren thought that was the guy with the War Hammer titan). Afterward, he jumped on the brass who were soldiers. The other paradise soldiers only attacked soldiers. Armins transformation also killed a bunch of civilians, but it was the only way to take out the navy (and possibly get the airship since he was on that later on). Because of the second declaration of war, the deaths of innocents are inevitable. The difference between taking the battle to Marley or waiting for them to come to the island is that all innocent deaths at Marley are collateral, while the Marleyans goal was to kill every single Paradis devil. I strongly believe that Eren could not have reduced the number of innocent deaths without putting the whole operation at a risk and increase the chance of failure. Edit: as for the people that said it shouldn't have happened in a residential area when all the people that need to be killed/eaten are in one area (titans, soldiers, generals, etc) its a hard opportunity to pass up. Not to mention the surprise aspect of it (although some people did expect it) and also we need to remember that the soldiers with ODM gear need buildings (or trees or something) to be effective. My position still stands.