Yes they are jewish ... which is an adjective denoting opprobrious behavior, which historically, is quite apt. (See slavetrade in kievan Rus)

Jehudi or Judeans (note Spanish Judeas; idem Latin) which makes jew and jewish a shortened version or bastardization, usually employed to denote discontempt.

Compare: jew coin, jew house, jew trick, to jew someone, Roman Jorre (From Dutch region of Twente slang word denoting an untrustworthy convert of khazarian origin).

It is a very old notion relating back even to Cornwall's tin trade way back. (also see Phoenicians)

Why would a population embrace a notion of contempt, except for a very specific reason?

Example from history: See Dutch rebels against the Spanish crown appropriating the contemptible notion of Geus/ Geuzen

From Middle French gueux (“beggar”), from Middle Dutch guyte (“rascal, good-for-nothing, freeloader”). (historical, chiefly in the plural) A supporter of the insurrectionist faction in the Spanish Netherlands, who became the enemies of the Spanish crown, formalised in 1566 (originally a polemic insult, but soon reappropriated)

That is before the 1581 declaration of independence called Act of Abjuration

The isigna worn by the Geuzen (beggars = rebels) had to sides. One: image of Philips II, King of Spain with the words: EN . TOVT . FIDELLEƧ . AV . ROY = in all loyal to the King Two: IVSQVEƧ . A . PORTER . LA . BEƧACE = until the wearing of destitution