(A continuation of
my basic principles, inspired by
this discussion)
In general, if everyone from group A (women, the poor, immigrants etc) just happens to violate seemingly coincidental and objective value B then:
(a) It really is a coincidence
(b) They're just inferior in general
(c) There's something skeevy going on with the way your values are contructed
(d) You're not applying your values consistently
Now (a) happens sometimes, like I have an intolerance to milk fat so tend to see french food as "inferior" but it's not that I have any deep seated aversion to the french. And I have no problem with those french dishes I can eat. That was a crappy example. A better one is the way that many societies associate black with the night, and thus scariness and evil, and afaict this has (or had) nothing to do with the racist representation of dark-skinned people as inherently bad, though the two have since become linked.
Most people will deny the possibility of (c) or (d), and once the "evidence" builds up (a) starts to look a bit shaky, and so the subtext ends up being (b). This is the justification for almost all modern intolerance, since it's no longer acceptable to explicitly say (or even think) "Group A is just naturally inferior".
But when you scratch the surface? Most of the time it is (c) or (d).
For an example of (c), classism relied on the marks of "gentility" being valued above all else, and those marks were things you only tended to get if you were upper class: the right accent, knowledge of the classics, proper etiquette, the right clothes etc. Thus, the lower classes were provably inferior! And if you think that doesn't happen now you obviously haven't encountered the idea of "white trash"/chavs etc. There are similar deliberately created reasons for the devaluing of women, non-european cultures etc.
On the other hand (to illustrate (d)), a lot of western christians will talk about how the entire middle east as a region is doomed to irrational violence because of the calls to violence in the Koran, despite the fact that the Bible has an awful lot of similar passages, so by that logic all of western europe/America etc is just as doomed.
But even if it is a coincidence you still have to think about the consequences of your actions: if you take an action against everyone who violates value B, and that adversely effects people in group A, well you have to keep that in mind.
This is why saying "It's not that I'm racist/sexist/ etc, it's just that I value *blah*" is a very weak argument, and you shouldn't make it without thinking very hard about where your values come from and how you're applying them.
Of course, "objective values" are different from subjective taste/opinion, and if you are willing to admit your subjectivity that can help ameliorate the "Everyone in group A just sucks" effect. You still have to think about the reasons for and consequences of your value judgements though, especially if your "personal taste" happens to correspond with a lot of other people's for (c) and (d)-esque reasons. For example, you can't help it if you think women are unattractive, but some straight women/gay men can use this as an excuse to be sexist which is bad.
It's important to note that you can't help having skeevy values if you live in a skeevy society, and you may not be able (or wish) to retrain ourself out of them. But it's important to be aware of where this stuff comes from and the effect it has.