Lots of people working on the Manhattan project did not know what they were working on. The core group of physicists did, but not many others.

I think you could get away with that excuse in 1945 when this whole system was first being created from scratch. It's been 80 years since then.

They knew the US was at war and they knew it was a government program for military purposes and they knew they were dealing nuclear materials.

A journalist not involved at all figured it out just fine, but at the very least it's not like it wasn't going to be a weapon.

Frankly though I wonder what the various judgemental people in these comments think about say, the tens of thousands of people who at the time were just straight up making artillery ammo.