The Levant area was very multinational. This is one of the things people get confused about in the Bible. Just because somebody is referred to as "A Jew" didn't necessarily mean they were of Hebrew descent or practiced the religion. Especially during Roman times the region was just called Judah. People of the era used the term "jew" generically to refer to people from that region. It didn't mean those people were Hebrew or even particularly religious.
Also the Hebrew people frequently drifted in and out of faith and frequently adopted the practices, religions, customs, and wives/husbands of other peoples.
In fact this is a major theme of the Old Testament/Hebrew Bible. If not THE major theme. It follows a repeated cycle of the people falling out of faith, bad things start happening, they beg and plead for salvation, God redeems them only to have the cycle repeat in their children's children.
So anybody who has read the Bible shouldn't be surprised when archaeologists discover pork bones or pagan idols among ancient settlements in the region. This is exactly what one would expect.
> How does it become pretty much the thing you remember every time you're out with your Jewish friends?
Because it is so conspicuous. Pork and pork products are used in a huge amount of foods and products. Even food that doesn't list it as a ingredient in restaurants frequently uses lard as part of its production.
So it actually requires a lot of effort to avoid it and one can't help but noticing when friends need to have special convesations with the waiters, etc.