Palestinians aren't a people because it's not an actual ethnic group. They are arabs. "Palestinians" is effectively a Pan-Arabist ideological construct, a literal Proletariat Nationalist race-class, constructed by the Left.

That being said, jews are a religion. Not a race, not even an ethnic group. Jews have ethnic groups within them, but they are not a race, have never been one, and never will be. So a non-practicing jew, is just: not a jew. Their religious practices may keep them generally socially isolated, but it also prevents them from actually having genetic uniqueness (because the bronze age religion doesn't understand genetics)

"White people" is a weird concept that has evolved over time. Typically it meant British Protestant, but the Americans kind of bastardized the concept to merge into the term "Caucasian".

White is a purely abstract concept, but there was a white culture, if you are referring to WASPs, effectively.

Caucasian is an abstract concept, in so much that is a container for both the category of humans indigenous to Europe, though it's a misnomer to act like Europeans originate wholly from the caucuses. Caucasians as a biological stratification can be identified as a series of underlying genetic markers.

There definitely isn't a thing such as "caucasian culture" because the indigenous populations of Europe are far too varied to have that low level of commonality. Even if a group of caucasians have a similar culture in another country that is outside of europe, it is because they are a group which has migrated, and developed a shared culture in that place and time. Which means you can't say something like: "Rhodesians whites have a similar culture, therefore they are an example of the uniform culture of all Europeans". You're going backwards in the inheritance of culture.

What is typically being done is "white", WASP, and "caucasion" are being intentionally confused as a mechanism of rhetorical warfare.