1: weed leads to cultural decay, meaning more homeless people, more littering, more crime, secondhand smoke, etc.
I don't believe that weed itself is a correlation to homelessness. If you're referring to substance abuse, you can apply that logic with any drug that exists such as cocaine/crack/heroin/etc. However, I don't disagree with your point of being a contributing factor to it.
2: weed has potentially negative health effects like schizophrenia and psychosis.
It can if you are frequently and constantly smoking weed all day. However, I believe there is a bit of nuance to this point. If you are someone who is a minor or whose brain has not fully developed, introducing chemicals that are not good for you are obviously going to do damage to yourself.
It's not a secret that if you smoke weed at a young age, it will cause adverse effects on your brain growth and development. speaking from personal experience, i started smoking weed at age 14 and my memory completely fucked not just from weed, but constant drug abuse.
so with that being said, i don't believe that weed itself causes health effects in most cases. if you are someone with an underdeveloped brain, or you have pre-existing medical conditions, then weed may not be the medicine for you
3: weed attracts stoners and drug addicts to red states like Texas, Florida, etc. This point might turn out wrong but is still relevant.
That point is new to me, I would assume it's more on the freedom aspect??? I used to be pretty liberal a few years ago, but covid has turned me into a real right wing conservtard. i can't refute that point because i'm not knowledgable on that
4: weed culture leads to the normalization of drug abuse and serves as a gateway drug to more harmful substances that harm communities and families.
i don't agree with the idea of "weed is a gateway drug", which has been something that's been pushed upon people for decades. when i started doing pills and snorting cocaine, my reasoning for doing it wasn't "damn weed isn't doing it for me anymore". it was "wow, i want to get fucked up and have a good time".
again, i think there's probably more nuanced than just that. however, i think we should note the difference between correlation and causation