You probably misunderstand the term ghetto. Any neighborhood where people of one persuasion congregate can be termed a ghetto. a;mpst all American Jews live in areas of NY, LA, and Miami where they associate with other Jews.
More likely you misunderstand the term ghetto, I refer you to the dictionary of your choice. Ghettos invole a level of compulsion, physical force, or simply economic or social pressures.
However, if ghettos are voluntary, how am I to understand the many derisive comments about most Jews having no religious values, just a bunch of secular liberals. They congregate only with Jewish secular liberals?
Intermarriage, around 50% in the Jewish community, they mail order Christian brides, who then settle in the Jewish ghettos.
This may come as a shock, but Jews associate with all kinds of people.
Wrong. Ghetto is a perjorative at its worst, and at its best indicates a forced living situation brought about by social or economic conditions. I don't know of any Jews that deliberately seek out neighborhoods based on how many other Jews live there. And I bet you don't either.
Yes and no.
You typically end up with "Jewish" neighborhoods because: (1) you walk to shul --- ergo, you live by it; (2) shops that cater to your needs (e.g., kosher restaurants, butcher) logically locate close by; and (3) eruv points (related to sabbath activities) are expensive and hard to keep up, so you keep them in close proximity.