Those aren't good examples.
Flesh Tearers and DC in general aren't really angry, they just think they're Sanguinius. Red Thirst is just vampirism.
Black Templars are about hate, not anger.
Night Lords are just sadistic crimminals.
Meanwhile post-heresy WE are pure, undiluted rip and tear with no pretentiousness to it. They're the sacred weapons of the actual god of brutality, and they wouldn't have it any other way.
Just my opinion tho.