I disagree that Europe turning on Israel has anything to do with shock at their cruelty. 2 things simply have conflated at the same time: 1) leaders hoped that Gaza would fade in the background and people would forget, but they never did, which increased its political cost
2) Trump betrayed Europe, which meant European leaders needed to find a way to signal both a) their disapproval of the new US and b) their security and foreign policy independence / self-sufficiency. Turning the heat on Israel was the easiest way to do this
This is in fact exactly what Lula did in 2010 to signal his intent to distance South America from the US - Brazil got the entire region to recognise Palestine. And it worked. Things were never the same.
The key thing to watch is the upcoming high level conference on the 2-state solution, which is the venue where the anti-MAGA west will make its move to distance from US leadership by having key states recognise Palestine
I really do not think Macron, Starmer, etc simply got too sad about Palestinians. They could not care less about them.
They are simply trying to kill 2 birds with 1 stone: appease an angry electorate and distance diplomatically and strategically from the US