Are Latinos on track of assimilating into white just like Irish, Italian, Polish before?

[Red Velvet]

I’m confused as to why Polish; Irish or Italian weren’t “white” at some point lol

Aren’t Poles “slavs” and Irish “celts” and Italians “romans”, three of the main European ethnic groups?

Was the definition of white for USA just “Anglo-Saxon” because of the English and German racism towards other European ethnicities? Funny though, as much of the USA comes from Ireland as from these other two countries.