It is not the topic in question which is debated instead it is the messengers sanity or intelligence which is called into question?
Something to do with UFOs, little green men and crop circles perhaps?
Generally the simple explanation is the easiest. If chemtrails really existed someone somewhere in the aviation world would know have to know about it. Given the grumbly, gossiping nature of we aviation folks, it would leak out.
Chemtrails don't exist. Period.