A statistical argument for prejudice

All "isms" be they racism or sexism are based on generalisations: whites don't make good basketball players, Indians can't sing etc or whatever.

Now, the counter argument to this is 2fold
1 - the generalisation is false
2 - the generalisation is valid, but because of individual variation, we can't apply a blanket rule, but must pick/treat everyone on merits

I want to engage with 2. It seems to me that in many circumstances, merely engaging a blanket rule would be quicker and more efficient than actually going through each case individually. For example, say I hate Croats because they are Nazis, it would take LESS time for me to refuse to be friends with Croats than to get to know every Croat I meet and discover his/her predilections.

People say "oh, you can't not hire a black man to be your scientist, black men invented peanut butter" or "you can't not sign a white man to be your power forward" blah blah. But the exceptions don't deny the rule. If we spent more times using a "good enough filter", rather than trying to optimise - satisficing instead - I think the overall gains would outweigh the costs.

the "good enough filter" however can sit somewhere between 1 and 2

1 'false'
2 'valid'

no problem with sitting somewhere in the middle

if 2 was 'true' then we would have to pick one or the other (based on what you have presented)

maybe you could get to know the croats who dont have swastika tattoos?

Racism has got nothing to do with whether the statement is true or false..

And here's a reason why...

"I don't mind that they work over at the factory, but I don't want one of those lactose intolerant people moving in next door..." or "Some of my best friends are lactose intolerant. But I sure don't want my sister marrying one...."
Say what?
Saying that people of African descent are more prone to lactose intolerance than those of Northern European descent is not racist, because, well, it's true. Right?
Which has, in my view, two answers. One is that yeah, one could argue that it is not racist to the extent that it is true. By my definition of racism it is racist because truth is not part of the equation of the use of racialized concepts. And there may be a problem because it singles out Africans as being the intolerant ones (in this case intolerant of milk, digestively).
To be fair, it is an example of a reasonable assertion that is not offensively racist. It is nonetheless race-based thinking, in my view, and does not escape being race based simply because it is correct. But, that is not the interesting part. The interesting part is the other of two answers to the question.
This is to say that the phrase "intolerance" itself is, in this case, terribly racist. Here's why.
Intolerance is a negative way of saying something. It sounds like a problem, or in this case because it is a dietary effect that has negative symptomatic consequences, it sounds like a disease or at least a thing that one does not want, or that is bad.
No one ever said "Hey, this guy is great. We love him. He's so, I dunno, Intolerant and stuff."
But I ask you, how does the following sound?
"Austrians are intolerant of strychnine. They get dizzy, they convulse and stuff, then they often die when they eat strychnine."
We'll, duh! Strychnine is a poison. Of course they die from it. Why single out Austrians???? This seems utterly off-base!?!?
Lactose "intolerance" is the same thing as being susceptible to strychnine poisoning. Normal.
Adult mammals do not drink milk. Why would they? How would they? Where would they get this milk????? ... Think about it.
But don't think about it too much. Just realize that fetal mammals 'drink' mother's blood, and baby mammals drink mother's milk, and adult mammals do neither.
But there are exceptions, and maybe that is a little weird. For instance, vampire bats do continue to drink blood as adults, but interestingly, not their mother's blood. Indeed, they drink blood of a different species! Ick! How Strange!
And humans do continue to drink milk as adults, but interestingly, not their mother's milk. Indeed, they drink mil of a different species! Ick! How Strange!
I told you not to think about this!
But how does this relate to the issue of race and racism? Simple. Normal adult humans do not drink milk, and do not have the enzyme to do so because that enzyme is not produced in adult humans, just as it is not produced in adult mammals generally.
Then, among humans, there are a few strange populations, including a couple/few from Africa and some Caucasians (and that's about it) who drink milk as adults.
These are the strange people with the odd behavior. They are the ones that should be labeled as different. But since the milk-drinkers are the Europeans who get to name everything and determine what is normal globally, the situation is reversed. As usual. White skin, drinking milk as an adult, blue eyes .... these are all mutations that are strange and weird or just plain bad for you. But in so much of the global discourse, these are the normal traits.
I prefer to never use the term "lactose intolerant" and rather, I use the phrase "adult lactose consumers" (alc ... ick).
(By the way, if consuming milk as adults was a trait only found in dark skinned people of equatorial regions, what else would Europeans say about those people? Don't think about it!!!)

btw, the post above is taken from http://scienceblogs.com/gregladen/2008/05/why_lactose_intolerance_is_a_r.php

Racism, sexism and all other similar 'isms' are a result of a very useful survival instinct that humans come pre-equipped with, it's up to each individual human to decide how much they want to moderate that instinct, but its benefits are very real.

Like Vad said, it's efficient, easy to be misguided but it has its merits.

I'd have to weigh the time spent selecting against the benefits I'd gain

This is a "good enough" theory

I think context is key really. I wouldn't have a problem with you as an individual applying blanket rules to something like friend selection. But if the State starting behaving like you did and began applying blanket rules in favour of efficiency where such resulted in unfairness to the individual then I would have a problem with it.