> Many Russians and Ukrainians in Eretz Yisroel are Goyim.
As mentioned in another thread, someone who always points at others, should be himself suspected.
They are obviously more intermarried than Israeli Jews (thanks to Zionists who brought them to EY and thanks to Arabs who refused to mix with them!) but not that different from American Jews. At least Russian/Ukrainian Jews have official passports that list nationalities and patronymics, so Israeli Rabbanut can figure out who is legit for marriages. Also, they have secular marriages that can be simply disregarded. And at the end, they are survivors of decades of prosecution and ignorance … way longer than European Jews under shoah… Probably, only Spanish marranos have a longer history of survival.
I am told that there is a special russian-speaking department with kosher Russian Jews who spend time checking those documents and calling up grandparents to confirm. So, I would say, if you are confronted by Russian Jews who were married in Israel, they have chezkat kashrus.
At the same time, in this country, you need to deal with non-O marriages and conversions; with O-marriages without non-O divorces, leading to mamzerim … So, I think we need to be humble here.