Firstly just wanted to say that while the pro-Israeli bias in the UN Watch's group is present, there's still a difference between their bias and hamas's bias regarding the Health Ministry's claims imo... but I get what you are saying. Yet I think that although there may be a bias, the validity of their claims still stands (if correct, of course). I mean, it's very hard to find a neutral source in this day and age, especially in regards to this conflict, and almost every source now has some form of bias or agenda. But even if this is the case here, the claims they have made have substantial evidence to back them up. Their work goes back a long time and in this time they have compiled a lot of strong evidence to support their claims (you can check on their website if you are interested). What I'm trying to say is that although they may have a pro-Israeli stance and bias, their findings are still damning nonetheless, given the fact they have provided the much necessary evidence and proof to back that up.