There were times when individuals did not work for someone higher than them on a pecking order, though that model is physically not possible in an industrial society, I think.
That being said, hierarchies can be made voluntary rather than enforced by threat of violence, and I'd argue that requiring all servitude to be uncoerced would lead to a better future.
By weighing all violence as immoral you are not ruling it out completely. You make it a last-resort, where you avoid one great injustice with a lesser injustice - a lesser injustice which you still face consequences for.
The alternative is morally sanctifying some murders, which leads to 'morally justified' murders being done by all political sides (since they each view themselves as 'the moral ones'), and which eventually gets twisted into the party in power murdering their opponents with impunity because it's 'morally justified'.