You can make 'medicinal butter'? That renders me incredulous.
THC is an oil. It will dissolve in oils like butter on a stovetop, which you can then just eat. Why does that make you incredulous? Fish oil is good for you, you can buy it as supplements, but you can also just slop some in an asian stew and it will do exactly the same thing for you.
I mean, you can eat marijuana straight up too if you want, but it tastes like ass.
but there are still significant effects from smoking marijuana (9% addiction rate, eventual memory loss/damage, general issues associated with long-term stimulant use).
Why is it your concern if I get myself addicted to marijuana, or if I have minor memory loss? Worry about your own brain, and don't use THC if you don't think it's good for your brain. That's up to you. My brain shouldn't be up to you.
This sort of "protect you against yourself" logic fails massively when compared to the 30 bazillion other things in the world that are WAY worse for you than cannabis that we do not ban:
We don't have laws against skydiving.
We don't have laws against driving in icy conditions.
We don't have laws against eating bacon every meal. (or cheetos and coke for lunch, etc. etc.)
We don't have laws enforcing exercise.
We don't have laws about picking up heavy objects using our backs.
etc. ad infinitum
Are you prepared to endorse all of those laws too? If we legislated everything that was of equal or greater risk than marijuana, we would probably all starve/freeze to death, cause it would be illegal to do much of anything except sit quietly in your living room and stare at the walls, and nobody would be shipping any food to us or mining any natural gas to heat our homes with...
Edit: we do have laws regulating driving and skydiving, for example, but they are just to make sure you don't hurt others by being a greedy company that cuts costs on packing chutes, or a driver that blows through a red light in a school zone. And I am all for marijuana safety regulations such as inspecting growers to make sure they're using clean, orderly facilities and stopping second hand smoke as mentioned above, etc. That's very different than banning.