More Palestinians were killed by the Jordanian forces in 1970, during the Black September when King Hussein declared war against the Palestinians refugees in Jordan to counter the fedayeen coup-d-etat.
The other (Gulf) Arab countries are well aware of the track record of the Palestinians. And at that time King Hussein took Pakistani Airforce help to kill his brothers from Palestine.
So this is the unity between Arab nations. They only want to show sympathy in Television and media.