Good call, here cannabis damaging effects are usually minimised and hidden under the rug.
And you will always, always find someone telling you “what about alcohol”
I get the "what about alcohol" argument from the standpoint of being able to make your own decision to do a drug without the government interfering.
But it's not an argument to prove that weed is harmless. Its definitely not.
As soon as someone says "what about" in a serious debate like discussion they've lost whatever respect and trust I had in them as a person.
Eh, "I don't believe your claimed reasons because your actions don't seem consistent with them" can be a valid things to bring up. Of course it becomes less so if you then refuse to hear any explanations that aren't the one you came up with.