Why would israel need to justify themselves further than they already have? They don't need to have plausable excuses, just look at every other thing they've ever said.
Israel has always been fully allowed to commit mass scale warcrimes against Palestinians and has always been fully subsidised by western countries to do so.
The iof have been doing this for decades while claiming it was in fact what hamas was doing instead.
Link to Independent article from 20004 about a Palestinian child they handcuffed to their jeep as a human shield
Look up 'IDF using Palestinians as human shields' and there are pages of photos and articles about this, 5 children have been used as shield by the iof this year that we know of.