Since when is "Ese" used in American "Spanglish"?
Solution 1:
In one sense, forever: In that particular sense...more or less since the 1970s.
I am assuming the dialogue you saw is from recent TV programming
I seem to remember from one of the episodes of Fear the Walking Dead that Reuben Blades was trying to describe the differences between the ruling body, and "us".
and it was more or less like that:
"Ese, ese no es como nosotros...ese is not us. This is not us."
or something similar.
Cannot find the script...but it works in the context.
I do not know if you will be able to narrow down the specific use in American television programming: it has a long use in Spanish, and any Cholo would probably carry over the nuance to daily use as it does not translate well.
The idea is that to use ese, esa or este, with the proper emphasis, usually has a pejorative sense when talking about people, even in Spanglish.
On the other hand, it is claimed that Latino gangsta members use the expression among themselves, as in
Hey homes...what up ese?
Since ese is usually considered pejorative, it is kind of like Afro-American's using "niggah" within their group: it is acceptable in the cultural group, but viewed unfavorably when used by outsiders.
As the Mara Salvatrucha got their start in LA in the 1970s...I guess you could date that type of particular usage to shortly after that.
On the third hand, there are some people who claim it originated with the Pachucos of the 1940s, the so-called zoot-suits. However, I cannot find anything to support that.