Many non-Ashkenazi (Ashkenazi being Jews of Western European/German culture origin) complain of such discrimination. It is a Western European/Israeli culture that discriminates against them - think of them as Israel's WASPS.
From what I have seen during my 26 years in thucking USSR/Russia - vast majority of what is now called "Russian Jews" are Ashkenasis. Given the history of Pale of Settlement - i.e. how Russia inherited most of its Jewish population from Poland (i.e. from Germany through Poland - hence Yiddish language) it makes a lot of sense. The only Sephardic ones I have ever seen or heard about while there were "Soviet Jews" from Central Asia (like Bukhara Jews). I do not know enough history to attribute Karaims. But both Karaims and Central Asia Jews are/were a distinct minority among Jewish population of former USSR.