They were all secret operatives under the Department of Defense, although Luke didn't know which divisions they were from.
Killing these people would be the same as Batman officially declaring war on the U.S. Department of Defense and the four main military forces.
Luke didn't plan to have Batman become a thorn in their side. In any case, he still had many other identities that could take that role.
This high-level Joint Research Unit was quite interesting.
In the beginning, it was similar to Sentinel Services. It mainly researched superpowers and tried to make them available to the American government.
This concept was actually no different from all super soldier projects; it was just the way the soldiers were boosted that was different.
But after Amanda Waller took office in recent years, she had been trying to add another element to it — to create a ready-made superhuman team for America's use.