Seriously though i don't really know what "white" is supposed to mean. Really. What does it mean? Are Spanish people white? Are northern Irish? Portuguese? Are Jewish people white? How about Palestinians?
"White" is a loose word not associated with any particular racial group, really, that means or meant "colonial ruling class", and some groups that used not to be thought of as white now are thought of as white because they have improved their status in society. So, perhaps Jews and north Irish are now considered white, but 100 years ago they certainly weren't REALLY considered white.
Another interesting case is Russians, Romanians, etc., who definately have white skin, but it's odd if they go around calling themselves white because they're NOT part of the ruling class.
That ruling class connotation is why people have trouble with "white pride", whereas if they said "German pride", or "British pride" you'd think they were simply referring to their own culture, whatever it happens to be.
But if you say "white pride" you are really saying something like "I'm from the group of people that run this country and I'm proud of it", and that pisses off the people who aren't running the country. You're supposed to maintain the illusion that everyone is equally represented in society and not draw attention to the fact that people from a certain number of European countries hold down all the top jobs.