Insurgent leaders and Aleppo

" Insurgent leaders say about 500,000 civilians, mainly those too poor or sick to flee, remain in rebel-held Aleppo..." Despite the cruelty of the Syrian regime--which is indubitable, as is the cruelty of the Syrian rebels--has it not been proven beyond a shadow of a doubt that all claims by rebels about who is left in a city are lies?  Do they not always claim that the people in the city are ALL civilians? Don't they also not claim that all those who die by government bombs are all civilians while all those who die at their own bombs are all combatants?  Syrian rebels are so adept at lying that they are worse liars than the regime itself.