Cannabis flowers (the part humans smoke) are not pollinated by pollinators

They are wind pollinated, much like corn

So the flowers are not evolved to look appealing to pollinators, like a tulip or whatever, and instead they evolved to disperse and catch windborne pollen. Which is why the marijuana 'buds' are shaped the way they are. It's the female flower that is hairy to catch the pollen from the air.

Corn also has weird flowers for similar reasons (the corn 'strings' play a similar role).

For the leaf shape... idk, no idea, but there are other species with somewhat similar leaves

And idk for sure, but there are theories the THC was acquired from bacteria. That the plant cell absorbed a bacterium similarly to the chloroplast endiosymbiosis theory, and then the bacterial DNA found its way into the plant DNA. Which is fascinating. No idea if this is resolved or not. If you don't know what I'm talking about look up the chloroplast endosymbiosis theory, it's amazing.