War in Aleppo and Western human rights organizations

Whenever the Syrian regime troops advance, all Western human rights and relief organizations call loudly for a truce and for humanitarian intervention.  But whenever the Syrian rebels advance, no one ever calls for a truce and for humanitarian intervention.  And when civilians in areas under regime control are shelled, there is complete silence in the West, but when civilians in areas under rebel control are shelled, there are loud calls for Western and Nato intervention and crocodile tears over the poor Syrians.  So only half the Syrian people deserve your hypocritical sympathy?