Nuclear research hub, the Idaho National Laboratory (INL), confirmed that it fell victim to a data breach on Tuesday.
"We're willing to make a deal with INL. If they research creating irl catgirls we will take down this post," SiegedSec wrote in a post announcing the leak on Monday.
Groups like this do it because they can, and usually not for any other reason. If they cared about anything they would make statements about how easy it would be for foreign governments to do the same thing they did, or work on taking down alt-right cesspool websites or whatever.
Reactor development HR departments aren't really national security targets. I mean MAAAYBE you could get plutonium if you blackmailed them, but not really.