Of course, baselss hatred because someone happens to be sefadi is something that is decried for generations by the gedolim – the chazon ish and the steipler both have letters saying chalilla vechas to reject a boy because he is sefardi..please do not interpret the above to mean that treating a group of klal yisroel bad is ok – it is terrible, sinas chinom, and it is without an excuse.
as a matter of fact, the chazon ish had many reasons for allowing the speaking of ivrit (all the modernishe will say ‘whats the shailoh??’), but chief among them was that if we all speak yiddish, we will lose the sefardim, who at that time had no infrastructure.
it is true though that what may be perceived as racism, might amount to simply not admitting a child from a family with sub-par religious standards, who just happens to be sefardi..every case needs to be individually examined.
sinas chinom applies equaly to all jews; there is no specific prohibition on generalizing them – on the contrary, ive heard many stories about gedolim referring to the differences between the poilish, galitziana, litvish people; their maalos and chisronos…that is not sinas chinom, and if it’s racist, well, let it be; the torah say nowhere that one should not be racist.