Bruce said Serena was being honest, but twisted the knife with June a bit. Whatever that means. Being a soldier in the crusades could mean many things though. Soldiers in Gilead by definition are called Guardians. They serve as the personal soldiers, bodyguards and servants of Commanders. We have yet to see exactly what he has done before being a driver. Going off the deleted scenes/previous plans for his backstory, he was just a security guard in the basement of the WH during the coup. Judging from that, the writers didn’t want him to have a big violent role and if they were to show his backstory in S6, I’d assume they wouldn’t make it much worse. I find it easier to forgive someone for guarding the basement of the WH then someone bombing the place or snatching kids from their parents.