It is a word that is just being thrown around everywhere.
Pro Hamas means someone who is a supporter of Hamas.
But the ordinary person who calls for a ceasefire is called Pro Hamas. Someone who says innocent civilians are dying in Gaza are branded Pro Hamas. Someone who says Israel are and have broken international law are branded Pro Hamas. Someone who says Netanyahu's government have people that could be branded far right are branded Pro Hamas.
It seems like if you criticise the Israeli government, IDF etc you are Pro Hamas. It is just a way to shut down debate and reject people who have valid points.