Not all Jews of course, but many who did come to this country were Bundists, who hate Israel and Zionism.
https://en.wikipedia.org/wiki/General_Jewish_Labour_Bund
My grandparents voted democrat. True. Times were different. And the democrat party was quite different then. We have all learned a lot since these times. I do not personally know any of these Jews who hate Israel. There are notable exceptions, of course. But many Jews have turned to the right after the experiences of the last 50 years.