I look at it from both sides. Yes, mostly the narcotics, methamphetamine... etc hurt more than just the person taking them. I have a newly found sister-in-law that is hurt emotionally everyday by the drug abuse that her mother chooses to do. Thankfully she lives with her grandparents and does not have to put up with her addiction draining every penny they have. However, there are some that I understand - pain remedies, marijuana - I understand that a little better. I have family & in-laws that have gone through every addiction. My husband has painful remedies of his mother choosing her drug dealing boyfriend and his drugs over him & his siblings several times. My brother-in-law has been going in and out of jail for the past few years due to battling drug addictions. At the same time I have friends and family that have addictions that really doesn't hurt anyone. For example (I will not name whom) but 1 person I know, stresses themself out more than necessary & all their responsibilities, worries, stresses, and ambitions usually hit them all at once. But smoking marijuana helps them sort through the jumbled mess in order to actually think things through and make more sound, responsible decisions. On the other hand- this same addiction does cause problems for those around them. It makes finding a reputable job almost impossible, which makes obtaining an income without killing themselves an almost impossible task as well. Also, it is a constant struggle for those who do use it in a productive manner to fight the addiction enough to be able to have control over the addiction rather than the addiction control them.
There is the good point that - in many instances Marijuana has many of the same effects of alcohol (yes speaking from prior experimental experience). So, I do think that if they allow alcohol legal and able to tax the H#@! out of it as well as regulate it and put stipulations on the use of it - why shouldn't they do the same for marijuana. It would cut down on the "black market" or street corner sales of it and the local & federal governments would be able to use the tax money towards bettering our country - whether it be to health care programs, schools, road repair, etc. They could also reduce the amount of money going to other countries - like mexico - supplying it to the US and using the money to fund war-for-profit, overseas gun sales, etc. It would actually put money back into the economy rather than out from under the table.