I haven’t read the full article yet (so this might be addressed) but I imagine that there is some significant self identification bias. People that self identify as Jewish in the west do so for a number of reasons, largely material but also for social reasons (basically socially sacrosanct).

For otherwise unremarkable westerners who want to feel unique they try their best to “embrace their Jewishness” which manifests as consuming ridiculous hasbara because its promoted as what a “good Jew” would believe. Being a uncompromising zionist is framed as the only acceptable position by most Jewish institutions. And doing so gets validated.