Allegiance is not an easy matter
When you say “Labbayk Yā Ḥusayn (pbuh)”; That means, ‘I am ready to help you’. Just as the martyrs of Karbalā, who helped Abū ʿAbd Allāh Ḥusayn (pbuh).
But, the helpers whom His Majesty Imām Zamān (mGehr) wants, are different from the helpers of Abū ʿAbd Allāh Ḥusayn (pbuh); not in terms of rank and status, but in terms of function.