Morality is a decision.
There's no virtue in following the rules unless we're capable of breaking them.
To integrate aggression, we replace external constraints with internal choices. Only then do our actions carry weight.
Of course, there are limits.
As benefactors of society, we rely on others for things like food, currency, and language.
But if we're dangerous enough to stand by our principles, all else is secondary.
To reiterate: harmlessness is not a virtue.
And once we understand this, we can become useful.