Jewish emigrants brought a lot of unrest to the US as many were confirmed Marxist, Communist and/or lefty Anarchist and vocal purveyors of “Social Justice”. These types were dedicated to overthrowing the established government much like the Islamic emigration into the west.
On the positive side of ledger, without the immigrant jewish scientists, we may never have developed the atom bomb and won WW II.
The main point the Spanish author makes is not that Jews were without faults, but that the replacement of Jews by Muslims is far worse.