It's nationally advantageous for the dominant US socioracial factions.
The US is obsessed with the idea of a "white" and "black" national mindset.
Mestizos haven't the sociopolitical clout of black America is all.
Mestizos prefer to be labeled white rather than Mestizo.
Mestizos are culturally, politically "co-opted" by powerful socioracial factions into silence.
Again I think you're mixed up maybe about the thread.
Most of the Central Americans in the US are not Caucasians but are mixed race mestizos, mixed with both Amerindian and European and sometimes African. So they are not Caucasians as you claim.
No Mestizo is not a race, it's a mix of races. That stated, Mestizo is an accurate racial label over "Hispanic" which tells you nothing about a persons racial heritage.
Answering "I'm Hispanic" tells us nothing about your ancestors because:
A 100% African person, a 100% Chinese person can be "Hispanic". Hispanic is not a race. It is a culture just as Christianity is a religion. Hispanic does not really tell us anything about you other than you perhaps eat tacos, which obviously isn't very telling about you.
However due to American cultural influence they are instead choosing white or Hispanic, both of which are not races.
No, white is not a race (holy god I have to say that lol?). European is a race in general terms. White is a complexion. An Arab can be white but not European, and a European white but not Arab. You understand?