How would you judge samuel slater and francis lowell, who brought secrets to the united states illegally?

Well they both helped to modernize/industrialize the U.S, so it depends which view point you would like to take. They stole the plans from england, who had successfully monopolized industrialization for almost a century, who would be upset at this loss of control and therefore business. However an American would probably be thankful for the industry that blossomed as a result of these actions.