It will come with time and wealth...
Not necessarily - this stems from the unique history and social structure of the USA. Afaik they don't have the same problem with calling black people "black" in France.
The media didn't mention he's skin color because it matters for them, but because it used to matter for Americans. So they were just saying: Look, America is changing.
One might argue with that. Still, vast amount of Poles, if not majority, consider black people to be slightly inferior, using examples such as Africa or that the highest crime rate is among African Americans. I do not aim at saying whether or not this is true, but this is opinion of a fair share of the population.
Another thing is that as Obama comes from a Muslim family, it changed the relationship between USA and mainly-Christian Europe. There are other social factors implied as well.
But bottom line, "czarnoskóry", "ciemnoskóry" or "Murzyn" are not considered pejorative in a normal context, as has been said previously. However, if you called a white person "Murzyn", it would be rather offensive (implying they are slaves and/or stupid). Still, Poles really don't care about black people, so this is not a major issue.