What a great question. The answer depends, if you accept my premise: The decision to relocate to the USA is usually a political decision and not a cultural one. By political I mean that we decided to leave our respective countries for many reasons, among them:
But in my opinion none of the reasons are cultural.
Americans of Hispanic Descent have made no such choice. Politically they are Americans as they generally follow the educational format of the USA (Anglo/Saxon in philosophy), the political format, the legal format as well as the social law format. But all this is political not cultural.
If we define Cultural as a group that has a common set of values and customs. (I know this is very general). Then Americans of Hispanic descent are Hispanic because the share the same values and customs that we all share as Hispanics.
If we are saying that you are more Hispanic because you are Colombian vs. Dominican, Argentine, Cuban, etc. Then to me this is more a definition of politics vs. culture. I have come the long way around to say that Americans of Hispanic descent are indeed Hispanic just a different Hispanic. Just like Colombians, Dominicans, Argentines, Cubans and Puerto Ricans are different.
What do you think?