The actress posted a message to her Instagram Sunday, just ahead of Christmas, and it again put a spotlight on the war going on in the Middle East ... which has claimed countless lives at this point, especially as Israel continues to try and hunt down Hamas.

She threw up a cartoon of Santa on his sleigh passing by a cart carrying dead/wrapped-up bodies -- as political commentary, no doubt -- and she added a very in-your-face caption.

It reads, in part ... "I HOPE THIS CHRISTMAS FEELS... WEIRD. I HOPE YOU CAN'T IGNORE THE FACT THAT YOU'RE CELEBRATING THE BIRTH OF A CHILD WHO WAS PERSECUTED AND TARGETED AND HIS PARENTS FORCED TO FLEE OT EGYPT."

Melissa goes on to say the exact same thing is happening to millions of Palestinians in that same part of the world all these years later ... all while "they are indiscriminately and relentlessly bombed." She ends her message with a simple and blunt "MERRY XMAS."

Of course, her position hasn't changed ... but the fact she's speaking right now is curious, especially since the director who was attached to the new 'Scream' movie she was fired from over her pro-Palestine views *just* announced that he's leaving the project as well.

Christopher Landon broke the news Saturday, saying he exited 'Scream 7' weeks ago without explaining why. What he did say, though, was telling ... writing, "It was a dream job that turned into a nightmare. And my heart did break for everyone involved. Everyone." He added, "I hope Wes’ legacy thrives and lifts above the din of a divided world."

Sounds like he might've bounced over this whole Israel-Palestine issue too -- and many suspect Jenna Ortega did as well ... even though other unrelated reasons were cited.