Look at it this way, all fraternities have a national office. National Office regulates how fraternities can write their constitution and tells them what they should include. Every single national office has a very strict drug policy. Unfortunately drug users (including us cannabis connisours ) are viewed as a greater risk management issue.
When I was pledging for my fraternity, I smoked with a few of the members, who informed the rest of the fraternity of my habbits. I was lucky in picking a frat that was very 420 friendly
Also, how many brothers did that chapter have? A unanimous vote in my chapter for initiation almost would never pass, we require a %75. It is really surprising to me that since every brother has the same rights and privileges as another brother, that it would take a unanimous vote to initiate someone.