Because it was a threat to American citizens. It was close enough to do major harm.
A majority had been farmers in Germany, and most came seeking economic opportunities. A few dissident intellectuals fleeing the 1848 revolutions sought political freedom, but few, save perhaps the Wends, came for religious freedom. The German settlements in Texas reflected their diversity.
1.General hymns of praise
2.Hymns of the Lord's kingship
3.Songs of Zion