system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do Jewish people have a certain look, but other religions don't?

Jewish people, no matter what nationality, all generally have a certain look. When you look at someone, you can sometimes tell that they are Jewish, eg Barbra Streisand looks Jewish, as do Neil Diamond and Fran Drescher. They also have their own names, eg Cohen. Other religions don't have their own names and you can't tell that someone is a Christian or Muslim just by looking at them. You can often make a good guess, eg someone looks Middle Eastern, so there's a good chance that he's Muslim, or someone looks European, so there's a good chance that he's Christian. 

How come very often you can tell that someone is Jewish just by looking at them? I thought that they were a religion, not an ethnicity?
gpt
Jew here! I'll explain.

Jews are a *people* first, and a *religion* second.

"A people," you say? Well! Yes!           
The Jewish People are sometimes called "The Hebrew People". The term is interchangeable. There are *two* types of Hebrews:

1) Ashkenazi Jews. These are your Eastern European "white" Jews! Think Jon Stewart! 

2) Sephardic Jews. These are your Middle Eastern *brown* Jews! 

90% of the time, when someone is referring to *The Jewish Race*, they refer to Ashkenazi Jews. This is a very unique ethnic group, with certain genetic characteristics that *only* apply here. Sadly, certain *degenerative disease* only exist in Ashkenazi people.. like *bloom syndrome* or *tay sachs disease*. 

In Europe, Jews are considered to be a unique and independent race. Remember: the holocaust was *racism* - it didn't matter if people converted. 

In the United States, our concept of race and religion is *different* - and Jews tend to get lumped with *whites* on the census. 

Now.. Judaism is the *religion* of the Hebrew People. And "Hebrew" is the language of the Hebrew People. 

However.. just because you're Hebrew doesn't mean you need to practice religion.. or speak Hebrew.            
There are plenty of Atheist Jews out there, like Karl Marx.. or ME. We are ethnically Jewish!           
Similarly, there's plenty of Buddhist Jews or Christian Jews. This is confusing because the term "Jew" refers to their ethnicity, not the religion.