To be fair, most gasses and even aerosols are effectively invisible to the naked eye. Not to mention viruses, prions, bacteria, spores.. some of which affect behavior (rabies, mad cow disease, and the famed cordyceps for ants).
Plus, the invisibility of a thing does not stop the conspiracy loons from building conspiracies around it. 5G RF is invisible, yet still being used by the government to control our brains. For chemtrails, the conspiracy is just going to turn into: "They're spraying invisible chemicals all over us to turn us into communists." There's no end to it.
It's funny how often the conspiracy types are both right and wrong. We have precision targeted ~~propaganda~~ content streaming straight to the tracking device everyone willingly carries, but they land on 5G being some sci-fi form of mind control.
It's some form of motivated reasoning. The same people who will tell you a secret cabal of billionaires controls the government will roll their eyes if you bring up the heritage foundation.
I would find CT believers fascinating if it also wasn't sad. I have one in the family and she lives below the poverty line and has been missing most of her teeth since her late forties (fluoride works, people).
They can't abide pretend child endangerment happening in pizza basements, but point out the Catholic church or Trump perving on Miss Teen USA contestants in their dressing room and they don't seem to care.
I hate to break it to you, but the individual chem-trails that you can only see with my patented tin foil glasses are more dangerous than the visible ones. If you knew about the people trying to control you, you would know all about this.
"Without those clouds the alien mind control rays from space will get you more often. You think it's deja vu don't you? Better get your tinfoil hat prepped."
Real chemtrails are already invisible. When you see a contrail it's because the jet engines have been poorly maintained to cut costs and increase quarterly returns to the shareholders.
You can’t reason (or evidence) someone out of a position that isn’t based on reason.