if you're so knowledgable about the rules and the staff ethos then you should have also known that trapping people with prop block is against the rules but i dont see why you should have been warned ,
i would have only given a verbal in a situation like this, but a warn is still valid as you did infact rulebreak it was just uncalled for and a bit harsh but still valid. as for his attitude it was for sure not what i expect from a staff member.