If I hadn't been sucked here I'd've been told as I've been Level Seven since I was assigned to guard the cube. But I know why Fury did what he did. Coulson was right with his last breaths to Fury. There needed to be a push to make us work together and his sacrifice did that. He knew the risks of going up against Loki and took them anyway.
I never was a fan of Operation Paperclip after the war. So of course it was going to be easy for HYDRA to infiltrate when they were around at SHIELD's beginning.