Hertiage-The Great Divider

I need to hop up onto my soapbox here for a moment and talk a little about the differences in race and ethnicity. I realize that most people seem to think the two are synonymous, but actually they are in fact, two different things. Let's just make sure we're all clear about this; there are only 3 known races in this whole wide world, Caucasoid, Negroid, and Mongoloid. Those are what they are called and there is no malice or disrespectfullness attached to those terms. In contrast there is an almost infinite number of ethnicity's out there, if you take into account all the combos, (enough put McDonald's and Wendy's to shame)!
Now that we have that straight, I would like to opine on why people not knowing the difference irritates me to no end. When I had a job requiring me to take down a person's racial data, White people always say White and Black people always say Black and Asians always say Asians. The only ones that ever had a problem with this are the Hispanics. This is not to be taken as a dis on the Hispanics since they're already getting it from both sides, but Homie Please! I don't really give a shit that you feel that being called White is an affront on your hertiage and want, nay demand, things broken down to your most basic region of the world. In my mind there is not much difference between being from Cuba and being from Brazil except the language. The same is true if you are from France as opposed to being from Sweden, i.e. you are still White. Hispanic is no more a race than being an asshole is, although they both probably have the same amount of numbers attached to their group! I just don't understand why some folks need to be so damn insistent on this point. We finally got Jewish people to stop refering to themselves as a collective people, a term they used for race, and to realize that religion does not equal what you are biologiacally. No, It Doesn't!
Along this same line, I also don't understand why on questionnaires there are all kinds of ethnic categories, but for White folks, there is only one choices. You can be American Indian, American Inuit, American Samoan, or African American but I can only be white. I can't even be American White, just plain ol' white. Now that I think about it, there are 2 White choices, but since I'm from English and Irish stock, I have to be White (not of Hispanic descent), that's how White I am. WTF!!! Sometimes, I'll write in my own category in "Other" as English, just so that they don't confuse me with any of those French M.F.'s.
If anyone can explain how on earth this is in any way PC, I would love to hear your thoughts on the matter, as I am at a complete loss for words.