Frankly, my question is why the OP wasn't offloaded in the first place. 30 minutes is below MCT. It seems to me that ground staff extended a favour, here.

In fairness to the ISM, cabin crew have no way of knowing which passengers are on a tight connection, unless ground tells them. But ground staff do know who's missing, and what their inbound flights are, so there's no need for rudeness there.