lit is shown that Frieza demands this, enslaved the saiyans and have pushed them to do his bidding. From what I remember, we pretty much get 0 saipan history pre-frieza minus GT and that's not canon.

All this to say "he was just following orders" holds up until maybe the cell saga. On namek I can give the man a lot of trauma and brainwashing and child soldier mulligans. Saving cell and letting millions suffer AFTER he's 'rehabilitated' and then does it again for Babidi, THAT makes him a space Hitler Jr