It's partly because of the guit of holocaust, but also because they just don't personally want to lift a finger regarding Palestine. It's a toxic mixture of inbred zionism, cold geopolitical calculus, appeasing the US in trying time in transatlantic relations, and neocon hubris. They maybe can bend to appease their own populations, but they really are not prepared to stop Israel and they would much rather help them. They just want the genocide to happen, but quietly and out of sight and no protests.

But it's not really just Gaza. They do this because of Ukraine, rising cost of living, European humiliation in from of Trump, falling economy, their own unpopularity, etc.... They are fearing the upheaval and people getting ideas when Brussels doesn't seem to have any of it's own. Remember that these are the same people who though that the end of the soviet union was the end of history and they are the culmination of humanity. They cannon accept being wrong or stepping down at this point.