An ethnic group is a social division, and social divisions obviously still exist.
Classes are social divisions too, as are nationalities, but the difference is that ethnicity is based on biology, whereas class & nationality is based on, basically, culture.
An ethnic group may define itself using racial criteria, which are based on perceived blood relationships, usually phenotype in practice. Think of "African Americans" in the United States, this ethnic group is racial in nature. But the "American" ethnic group is defined only by a common nationality (not the same as legal citizenship).
There is no "American" ethnic group, just as there is no "British" ethnicity. Broadly speaking, in the UK you have historically had the various Celtic groups (Welsh, Scots, Cornish, Irish), and the Anglo-Saxon (English) groups (along with a smattering of all sorts of immigrants & invaders like the Romans, Vikings, Danes, Normans, blah blah blah).
In other words,
race. The current politically correct phrase in the UK is "Black & Minority Ethnic", and if you ever have to fill out forms for Human Resources or equal opportunity purposes etc, you'll be asked to pick your
ethnicity in the UK along the lines of "White / Black / Asian / etc etc etc". Perhaps thinking of ethnicity as the subdivisions of a race is the best way to think of it.
(Incidentally, why is it these forms almost always lump black people under a single category, but don't do the same for Caucasians - as the Rwandan genocide etc shows, Africa is hardly home to one vast, amorphous race or ethnicity...)
If ethnicity meant things like cultural traditions etc as some here are suggesting, then someone clearly needs to tell Her Majesty's Government (and a lot of other people besides), because there is no common "white" culture etc.
Here's what you say when signing up for the dole in the UK for example:
- White: English / Welsh / Scottish / Northern Irish / British, Irish, Gypsy or Irish Traveller, Other
- Mixed: White & Black Caribbean, White & Black African, White & Asian, Other
- Asian / Asian British: Indian, Pakistani, Bangladeshi, Chinese, Other
- Black / African / Caribbean / Black British: African, Caribbean, Other
- Arab / Other Ethnic Group: Arab, Other
- Prefer not to say
If it looks like a duck, swims like a duck, and quacks like a duck, then it probably
is a duck.
Here's another example of why the "ethnicity is culture" argument fails: take the USA. The USA was founded on principles of liberty and all that jolly nice Enlightenment stuff. Therefore presumably, the American "ethnicity" will mean buying into those values (or whatever you want to define US culture as). In which case skin colour etc has absolutely no bearing on the issue whatsoever, and the issue is essentially one of culture or patriotism (or even nationalism). Putting down "Republican" or "Democratic" etc makes a darn sight more sense in that case than putting down "Black" or "White" or whatever. Instead though, the obsession is with your skin colour and ancestry - ie, with your
race.
In the case of Marie Curie, Wikipedia gives her parents Polish names, notes they were living in Poland (then part of the Russian Empire) when she was born, and so on - based on that, I would assume her to be an ethnic Pole, but who became a French
national (ie citizen) later in life.
+
Now, back to our scheduled squabbling over space fighters

...
Latency. Strictly speaking the tactical advantage of a small manned craft that is operating in real time, is going to be ENORMOUSLY more viable and useful than a drone that would need an operator that is dealing with seconds of latency over the distances that could be potentially involved.
If such reaction speeds matter, then you're absolutely right. However, I think it's quite possible to posit scenarios whereby reaction time is of minimal importance. Drone missile buses for example - if they don't need to dodge point defence fire because they have a longer stand-off range... well, reaction time isn't a huge issue in that case, because you can shoot & scoot long before the enemy has much hope of doing anything to said drones.
Alternatively, scouting out sensor blind spots behinds planets etc should be fine too, because "someone shot our drone down" is (a) safer than losing a pilot, and (b) still provides you with useful intel

.
In general though I agree: the more important the OODA loop becomes (observe, orient, decide, act), the more important it is that latency be cut to a minimum. Dogfights in practically
any medium will, all things being equal, favour the side who have nanosecond response times over those with millisecond response times.