No. God created THC in the pot plant as an insecticide--the chemical kills bugs that eat the plant.
It is our use of a natural insecticide for a purpose for which it was not intended -- for recreation -- that is evil.
Strange action for a Deity with "An Inordinate Fondness for Beetles"
"Not intended". You can't be real!
Did God "intend" that chicken eggs should produce new chickens, or did God intend that chicken eggs should be manufactured in warehouses where a hen never moves from her perch from the time she's placed there until as many months or years go by that she can no longer produce eggs? Is that what God "intended".
Ah, so man has a brain and experience and he learns to investigate everything in creation, and in doing so he discovers all the chemical properties of everything, and he finds many chemical properties that nature uses for the survival of the plants and animals and man figures out how those properties might help, or hurt him. And some he finds he must be careful about their use, they can help as well as harm, depending on how careful or careless we are. None of those properties are "evil".
There is nothing "evil" about THC and there is nothing "evil" about its affect in human chemistry. Now then, if you want to posit that someone who turns the constant use and over-indulgence of the chemical into their own addiction, is doing a morally self-abusing thing?; that I would grant you. But the THC and its affect on a person, in and of themselves are not "evil".