Just a quick history lesson..

Palestine use to be called Philistines by Israel. Under the Greek empire was when the region was first refer to Palaestina. And the name stuck ever since. It was the Arabs in region back in the late 80's that adopted the Name Palestine as their official countries name and therefore, they are Palestinians.

And San Antonio was named and founded by the Spanish, not Mexicans, in the early 1700's. Germans started to inhabit the city in the early 1800's, which is why German towns like Fredricksburg, New Braunfels, etc congregated around San Antonio. According the my Grandfather, there wasn't that many Mexicans in San Antonio when he was growing up. They started migrating (legally) there in 50's and beyond (size of San Antonio doubled from the 40's to the 50's). My Grandpa was born in the early 30's.

So yeah, Illegals didn't name San Antonio, more like invaders, which the Spanish were. And two, the Arabs in the region name themselves Palestinians, so yes, there is such a thing as Palestinians. If you contest, then ask Yassir and co. why they chose that name for themselves.
I don't give a what they were called. The Philistines were never Palestinian, and the reverse is also true. There is no official country of Palestine. There's debate on the statehood of it, and it's nation dependent. San Antonio was Mexico... so..