Why is it that an extended olive branch often turns to a clinched fist of hatred?

Why is it that an extended olive branch often turns to a clinched fist of hatred?

United we stand, divided we fall.

United we stand, divided we fall.

We are one people and will act as one.
[Ger., Wir sind ein Volk, und einig wollen wir handeln.]

We are one people and will act as one.
[Ger., Wir sind ein Volk, und einig wollen wir handeln.]

In union there is strength.

In union there is strength.

Their meetings made December June.
Their every parting was to die.

Their meetings made December June.
Their every parting was to die.

Oh, shame to men! devil with devil damn'd
Firm concord holds, men only disagree
Of creatures rational.

Oh, shame to men! devil with devil damn'd
Firm concord holds, men only disagree
Of creatures rational.

So powerful is the light of unity that it can illuminate the whole earth.

So powerful is the light of unity that it can illuminate the whole earth.

I know that my unity with all people cannot be destroyed by national boundaries and government orders.

I know that my unity with all people cannot be destroyed by national boundaries and government orders.

The plastic virtues: purity, unity, and truth, keep nature in subjection.

The plastic virtues: purity, unity, and truth, keep nature in subjection.