Why Did The Aliens Eat Me And My Family?

When the aliens came to Earth we welcomed them with open arms. The was no reason not to.
I agree they're free to settle here. But they ate me and my family.
And we manipulated that alien-
From within it's stomach-
To kill all other aliens-
They wern't happy-
And the war nearly began-
But then we decided that peace was just great.
And isn't it just.