Seriously, what Israel is doing today is no different from what the Nazis did before and at the beginning of World War II, extreme nationalism, illegal expansion, annexation of foreign territory claiming it historically belongs to them, propaganda using the latest technology, terrorizing neighbors, military at the center of society.
It’s more that I think there are multiple factors, one of which is how much politicians in power represent the will of the people.
For example, a nation being allied or not to the US also seems to infliuence their support or not for Israel whilst it commits a Genocide.
I would be surprised if that p-value is close to 1, but I would also be surprised if it’s close to 0.
Yes, because pissing off the US as an ally is generally an unwanted outcome and they are staunchly pro-Israel?
Except that for nations inside the EU that’s a lot less so than for small nations outside the EU, mainly because the main tools that the US can use to pressure nations are military - which if done against Europe would very likely elicit a reaction similar to that against the Russian invasion and destroy NATO and the entire tapestry of US alliances in the West - and trade (such as Tariffs) which the if the US tries to impose on a single EU nation will, due to EU treaties, treaty elicity a response from the entire EU, a market of 470 million people on the top 25% of wealth in World terms, so that would end up costing a lot more to the US than to said nation.
Whilst it’s totally understandable for small and mid-sized nations which are US allies and outside trade blocks like the EU, to just go along with US foreign policy - even as extreme as supporting a Genocidal state mid-Genocide like this - because they have no other choice, even tiny EU nations do in fact have a choice because the US would have to go against the whole of the EU to significantly hit those nations.
So whilst the likes of New Zeeland pretty much have no other options than to go along with the US on this (at the very least to just shut up and act as if nothing is happenning), the likes of The Netherlands definitelly have other options and yet their politicians have been dragging their feet on stopping support for Israel.
This is probably why all nations which are allies of the US and were almost from the start overtly against Israel and their Genocide are in the EU (such as Spain and the Republic Of Ireland).
All this to say that no one single factor decides it, IMHO.