combine that with the fact that no one trusts the government to tell them what drugs are dangerous anymore. maybe you never did, but many many people used to not do various drugs because they trusted that they were illegal for a reason. the current state of marijuana being federally illegal and clearly not hurting people that bad has made that much much harder to believe.
It's true, there are two plants native to the area that produce the psychoactive compounds also found in Ayahuasca. Peganum harmala aka harmel or wild rue, and Acacia confusa aka ayangile or formosan koa
The former is a short, bushy flowering herb, and the latter is a variety of tree that Noah might have used to build the ark.