If we have a weed epidemic then we certainly have an alcohol epidemic too, as well as an obesity epidemic, as well as a traffic accident epidemic, and so on.
Making everything that can be harmful to some subset of the population illegal is not the way to deal with these issues. It's reductio ad absurdum into a totalitarian nanny state that literally controls your diet and makes you drive 25 mph on the highway.
It's not the government's job to make everything that could possibly hurt you if you overdo it unavailable to you.
I agree with you that cannabis can be very harmful to some people, and that the risks are often understated. But if you want to help people who are susceptible in this way, the solution is to help them realize they have a problem, develop self-discipline, and understand that while cannabis may be harmless to many people, for them it is not, and what works for many others (occasional moderate use) won't work for them.
In short, people with this issue should take responsibility, join a 12 step program, and fix the problem in themselves rather than expecting all of society to adapt itself to not trigger their addiction. That you can't use it in moderation doesn't mean no one can, just like there are probably many things you can do in moderation that other people aren't able to.