He says he wants the "man-machine" built with the likeness of Maria in order to "sow discord" amongst the workers. Maria is the one who is preaching a message of hope/faith and therefore keeping a revolution at bay. For how much longer, who knows. The point is, she is giving the workers hope and preventing violence.

Why would Johann want a version of Maria that encourages a revolution (death to the machines!)? It is in Johann's best interest if the workers stay succumbed, as his bourgeoisie lifestyle is dependent on their work.

(First post, sorry if the tags are bad.)