Suppose they did know beforehand, had the plans, but didn't take any measures to mitigate the risk.
You don't think that makes them appear incompetent or malicious? If they knew in advance but did nothing, that would be admitting to permitting the deaths of their own civilians. That's not exactly good PR, like you suggest.
They are certainly bigoted, but I think you are vastly underestimating the totality of the IDF's mass surveillance of Palestinians.