All the opinions you like to post here count for nought. The rules are very clear. Caught doing drugs, get discharged. The policy is zero tolerance. Everyone knows so no excuses. Fine to discuss the pros and cons here, but that won't change the rules.
There have to be clearly defined rules, without room for doubt. Rules open to interpretation lead to injustice. A bit like one person here discussing the rationale behind the rules and still being a member whilst another expresses a view and gets banned.