I would never make light of alcoholism in the priesthood, which is, as you say, a very real problem, just as I wouldn't make light of the very real dangers of drug abuse. 

The issue is the double standard that says recreational alcohol is fine but recreational marijuana isn't. The only difference, as far as I can tell, is that alcohol is an acceptable part of our culture -- especially within Catholicism -- and pot isn't. When abused, both substances can be destructive.

If the bishops want to teach about the virtues of moderation and temperance, I fully support them. But when they stray into trying to influence public policy on marijuana while fostering a culture of recreational use of alcohol, they lose me.