The gentleman who wrote Alice in Wonderland was a reverend and a teacher, as well an amatuer photographer. The only harmful chemicals he was subjected to were that of of camerea's flash, which was standard in the day, and the pain killers of the day. Which by todays standards were yes, drugs, but back then that's how things worked.
Lewis Carrol did not experiment with drugss, he never molested Alice Lidell, and he was not a pedophile.
Being a teacher he practiced great theology on the advacncement and evolution of language, as showcased in Jabberwocky.
He was not some nut or a drug addict. It's simple BS that some random person began sppreading about him and stoners thought was "cool".