Brad is a very private person. I applaud his honesty and openess on this issue. To me, it appears to come from sincere remorse and a desire to deal with his life in better ways. How often do you see that from athletes, especially when it comes to this subject?
It's easy to call someone weak, because they admit to being stressed and having issues stemming from their childhood. That's exactly why so many men, in particular, won't admit having trouble coping or try and get help with their problems.
Everyone has ways to deal with stress and my guess is that for most people it's usually not beneficial or healthy. People are "addicted" to a lot of negative habits to deal with stress.
Over-eating, gambling, smacking the wife or kids around, drinking too much, watching TV for hours every day, getting into debt, sleeping too much, picking fights, driving fast/recklessly, porn, cigarettes, chewing tobacco, bulemia, cutting, stealing, lying, infidelity.
The list is endless. Some of those have worse consequences than smoking pot.
To me being strong isn't about having no habitual negative behaviors, it's about being willing to admit you have them and taking steps to do something about it or at least trying. I wish Brad all the best.