These are very anecdotal and indeterminate arguments.
You have seen a lot of kids' lives destroyed by smoking weed? That's hardly a quantifiable observation. You can't use the limited sample size you've personally observed to make an argument in the aggregate. I know plenty of successful people (and kids) who use marijuana regularly. That doesn't mean that everyone can regularly use marijuana and be successful. A sample size should be diverse and numerous to provide an accurate representation of all marijuana users.
It's also a logical jump that I don't understand to identity weed as the factor that caused kids' lives to be "destroyed." First, what do you mean by "destroyed?" That's a completely subjective metric. For example, does "destroyed" mean ending up in jail? Does "destroyed" mean dropping out of high school, college, etc? Does "destroyed" mean causing familial relationships to suffer because of the drug use? Does "destroyed" mean ending up in therapy?
I know someone who dropped out of college and smokes weed every single day and has very few friends. By your usage of the word "destroyed," his life is destroyed. But he's honestly happier than 99% of the people I know who graduated from college and are working 40-50hr/week jobs or went to graduate school or started a family. He works manual labor, loves it, and pays his bills. He's completely happy and content with his existence. Has his life really been destroyed by weed?
There are two errors here. The first is that you can't use your personal subjective definition of the word "destroyed" to say that someone else's life is destroyed. Second, you can't definitively say that weed was the cause. Maybe the kids whose lives were "destroyed" had underlying conditions and weed use was merely the manifestation. Maybe the real cause was physical or emotional trauma, and weed was actually helping the kids. What I'm saying is that it's slightly judgmental and logically incorrect to look at someone who is struggling in life according to your definition and identity a drug as the cause of those problems with no evidence.
The same reasoning applies to your arguments about weed's addictiveness. The fact that some people told you that it is addictive is not hard evidence. Even if weed is addictive (and let's assume so for now), we don't categorically outlaw things from society that are addictive. People can get addicted to caffeine. People (like you mentioned) can get addicted to alcohol. Hell, I know people that are legitimately addicted to pizza. But "addictiveness" isn't a factor in the calculus of what should and shouldn't be illegal.
At the end of the day, the arguments that weed is some impending apocalyptic drug that "destroys lives" and is "addictive" and is a "gateway drug" are mere facades. The truth is that society looks down upon the choices that adults make in their personal lives to use mind-altering substances. The truth is that our country spends billions of dollars policing and imprisoning people who want to smoke quietly in their basements and watch movies and eat food. Trying to reframe this debate as anything other than a moral debate is reframing the issue.
