If you go to a shul you will realize that everyone, or almost everyone there, is white. Even if you go to modern progressive shuls you will still realize this, maybe such a shul managed to bring in one or two black guys among hundreds, but it will overwhelmingly dominated by whites.
Is this because Orthodox Jews are racist? Well they are, to an extent. They do very strongly believe in Jewish superiority over the non-Jews. And of the blacks they think they are a cursed group of people by Noach destined to live lives of slavery. These kind of ideas already make them racists.
However, to be fair, Orthodox Jews are not as racist as many of the bloggers make them out to be. There are many different forms of racism in the world. There are racists who want to rid the entire world of opposing races and only have their own kind. These are usually white nationalists or the Nazis. This is worst kind of racism.
There is a kind of racism where you hate the different races among you but you have no plans to dominate them, or oppress them. You just feel hatred towards a group of people. This is the kind of racism you do sometimes find in the US with regard to Mexicans. Because Mexicans are "stealing our jobs" so some people hate them for job stealing. Note that this kind of racism is not like the nationalists kind above. The Americans who hate these Mexicans for job stealing only hate them as they now see themselves as victims of undercutting, not because they are nationalists.
The least lenient kind of racism is to judge the virtues of others by using their race as a factor. This is the kind of racism that is all over the world, you see it on TV all the time. There are policies that use this kind of racism - like Affirmative Action. This is the best kind of racism as it does not have any kind of hate associated to any group of people, it just fails to look at people individualistically, but rather collectively. But this kind of racism does not carry any messages of superiority or hatred that the others ones do.
The kind of racism that Orthodox Jews have is a superiority complex. They think of their own kind as better than the world around them. Orthodox Judaism is a religion, yes, and so their superiority is partial religious superiority. But Jews are also in a way a kind of ethnic group. One can determine if one has any "Juden blutig" (Jew blood) in him by DNA tests. And Orthodox Jews, as an ethnic group, still insist that the Judenblutig makes Juden superior to the people of the world. Thus, Orthodox Judaism is racist in that it carries with them the message of superiority.
However, this kind of racial superiority does not carry with it a message of hatred. I know the Orthodox Juden quite well. I do not really sense a feeling of hatred among them to black people. They do believe they are superior to blacks, and they do often make jokes about blacks. But they do believe in their jokes. So when they say the theory of evolution is true, for blacks, as they descended from monkeys, they do mean it seriously in that they think they are superior to blacks. But there is no hatred. They hire black janitors to work for them in shuls. And they treat them with respect. They might have black neighbors with whom they are very friendly. They even can speak positively of these people at the Shabbos table.
So I think it is fair to say that Orthodox Jews do not have the hateful kind of racism towards other people, but rather they have the superiority complex kind of racism towards themselves. It is like having a dog. You have a dog as a pet, you can love your dog, be friendly with it, but you will always see it as inferior to you. This is essentially the kind of racism that Jews have.
Let me return back to what I started talking about - an all white shul phenomenon. The reason why Orthodox Jewish shuls are white (or almost all purely white) is not because they ban black people (or other kind of people) from entering. If you are a black person and you enter into their shul they will not say anything. They will not stop you in any way. Even though you would be black they will recognize you as a Juden before a black. So they will ignore your blackness and just accept your Jewishness. As I said since the Juden are not the hateful kind of racists they will not be bothered with black people coming to their shul. I have seen black people in shul, and asian people in shul, it is not very common, but it does happen. And when it happens nobody cares and nobody talks about it at the Shabbos table.
The most basic, and the best, explanation to why shuls are an almost all white phenomenon is simply because Orthodox Jews marry other Orthodox Jews, and hence most of the Jewish people will be white. The only way to have a black person in shul is if he converted to Judaism, which is not too common because Orthodox Judaism is so crazy that essentially only those born and indoctrinated into it will remain Jews.
So yes there is Jewish racism but it is not as bad as many other kinds of racism.