Why do non-Jews bashing Israel claim to be Jewish?

JPost

Defending his participation in the latest flotilla operation in an attempt to break Israel’s naval blockade of Hamas-controlled Gaza, Gabriel Matthew Schivone, an American university student, stressed in a late June Ha’aretz opinion piece that he is one of a growing number of young American Jews seeking to disassociate himself from Israel.

There is, however, a rather large factual wrinkle with Schivone’s account – he appears to have falsified his Jewish identity.[...]