we have made the difficult decision to have you step down from your volunteer position, effective immediately

These people haven't even mastered the English language, or more likely are deliberately corrupting it. You can ask someone to step down, or they can choose to step down (even under pressure) but the term itself means an action initiated by the person in question. You can fire or remove a person, but then they didn't "step down".

It seems like a little thing, but I know the choice of words was deliberate to try and falsely soften what they were saying