I agree with you. What rsaeon mentioned about sparse posts is not a rule, and your restriction appears to be arbitarily applied.
The moderation here is completely untransparent IMO, and not at all up to par. Just because someone is a volunteer doesn’t mean they don’t have the responsibility of being transparent about moderation decisions and the reasons for them, especially because the decision is outside the posted rules. However, that’s the way it goes for this team, and I wouldn’t hold your breath for anything different.