Because someone doesn't adhere to your standards, they are weak? That's a pretty poor outlook. Besides, there are perfectly safe ways to consume marijuana that aren't destructive, as with just about any other substance.
Tell me how exactly you safely consume marijuana? Please don't spread disinformation like that. I am not the one to judge you, but if you through all means try to good-talk your faulty behavior, this is a sign of addiction.
I encourage you to read the following page and seek help before it drags you down to a place you cannot recover from. It's not too late.
http://www.helpguide.org/mental/drug_substance_abuse_addicti...
For some however, it is a very real solution to problems like anxiety, insomnia, depression, low appetite, etc. Marijuana often has fewer side-effects than medications prescribed for those same ailments, making it a better option for many. That is how some people justify consuming the drug, and I think it's pretty narrow-minded to assume anyone who makes such a justification is an addict.
A natural process applied by our Creator. Amplifying this deprecation of your body by using drugs or other substances is bad form. The more so if you are fully aware these substances do that damage.
There it is
You need to do your own research as opposed to looking at government-funded studies which are only funded to show harm. Start with www.leafscience.com and take it from there.
Do you drink alcohol? Coffee? Asprin?