Eh, I kind of have to wonder about the addiction blog info. Read up on the endocannabinoid system. Your body is practically hard wired for cannabis.
Regarding health, all things should be taken in moderation. You can develop a number of issues from eating too many carrots...
Also consider the negative impact of the War on Drugs. Prohibition simply does not work. From it's inception it gave us the mafia and violent crime. Ending prohibition immediately dropped the violence.
Modern day prohibition has enabled drug cartels in the same way as the mafia. That's just they way black markets work. If you make something illegal, then it will be marketed by criminals who, because of police forces, will not hesitate to use violence to protect their market. Look at the violence in Mexico. Ending prohibition for MJ will have the same affect as ending alcohol prohibition.
Consider also the wasted prison space for potheads. Not worth it. Also, being a felony, a largely benign plant traps people into poverty as being a felon is all but a career ender.
Consider the problem in Dublin :(
I don't know how we can legalise a drug like heroin, but it's a huge issue in my city and destroys lives. And gun violence is escalating along with the market!
I believe that Portugal has shown us how to handle the problem. Decriminalization paves the way for actually treating the problem as a health issue rather than a legal one. The result has been a decrease in new and repeat use.