I'm not convinced that 'chemtrails' purpose is to slowly poison us. A simpler reason for 'geoengineering' and creating artificial cloud cover could be to block foreign spy satellites from getting a good look at what might be happening on the ground below. While it's still possible that these high altitude aerosols cause health problems, it seems like creating a 'fog of war' over sensitive activities would be a better explanation than simply trying to poison americans.