There are weed addicts. My college dorm had about half a dozen students jonesing when all the dealers (5-6 in our area) went home for the winter holidays. Did anyone lose their job, get in a wreck, end up in the hospital, or die from it? I seriously doubt it.
I'd say alcoholism and binge drinking are far bigger threats. You know, like my roommate who nearly died from alcohol poisoning on his 21st birthday from downing half a dozen shots of everclear and more.
The magnitude of harm, impairment, and life dysfunction for substance abuse varies by said substance. Weed addiction isn't nothing but it's not tobacco, drinking, or meth.
I'd said the biggest harm of weed is people who smoke it unfiltered and inhale microfines and ultrafines more so than filtered tobacco cigarettes. Dabbing could be potentially better, but so much of the market is grey and black that there's not enough research or uniform safety standards on producing healthy inhalation products.