"But the Church's job is to form the lay to then live, vote, work according to the will of God."

You may be seeing this from the perspective of one who believes the wall should be built.  I'm not.  Although I do believe the wall should be built, I wouldn't criticize the Archbishop for being vocally against it, even to the point of calling those who cooperate with Trump "traitors" --- IF they were indeed traitors.  The answer to that depends on whether the Mexican workers were acting strongly contrary to Mexico's best interests.  By helping build the wall, the workers keep from leaving those Mexicans and others that Mexico wants to get rid of.