The well known phrase is "One man's terrorist is another man's freedom fighter". I Imagine from their point of view, Israel is the 'terrorist' group, routinely bombing apartment buildings etc and that their actions are a proportionate counter (recent events nonwithstanding!)
Both sides of the current conflict have/are committing atrocities, but the reporting of those atrocities should be as factual and unbiased as possible.
As long as they are balanced, if you only ever have opinion pieces from one opinion, your just being biased by proxy.
This can lead to being over balanced though and inviting climate deniers etc.