They try to be objective, but nobody blames any media for siding against ISIL.

As for Israel, I feel like Al Jazeera isn't one-sided; there simply are more articles about Palestinian deaths because there are more Palestinian deaths. Even when around 20 Israelis across a few attacks died at the end of last year, with each death heavily reported around western media, a comparative death toll puts it into perspective: http://www.aljazeera.com/indepth/interactive/2015/10/mapping.... It seems that one side simply has better weapons, and so, causes more deaths.