Sheer ignorance and utter disbelief

A sociology professor of mine told me a story on Tuesday that I haven't been able to let go from my thoughts.

 He was riding a Chicago city bus on his way to a Blue line 'L' stop Tuesday morning.  The passengers from front to back were a mixture of races, colors, ethnicities, and personalities.  Everyone was wearing there own unique clothing style and kept to themselves for the majority of the ride as most rides go.  Sitting up front in the first available seat was a middle-aged (most likely in her 50s/60s) white female who looked quite pleasant at the time.  Nobody thought anything of the woman up to that point in the ride, so at that instance everything seemed to be unfolding normally.  The bus pulled up to the next stop where a group of 5-6 customers were expecting to get on.  The first customer stepped up and walked to the back.  The second, found a seat closer to the front.  The third, same thing.  Eventually, the last customer to get on the bus was a middle-aged black woman in her 40s.  She paid and turned around to find an open seat, but hesitated as her eyes perused the bus layout.  Before she could choose one, the bus started moving quickly and forced her to pick the nearest available seat, right next to the white female.  The white female, now with a very confused/annoyed look on her face turned to the new black customer with an very powerful glare.

"What are you doing?" she asked.  The black woman turned with a puzzled look on her face and said, "What do you mean? I'm not doing anything.  Just sitting, " she replied.
Now with an angry look on her face, the white woman responds, "You can't sit here.  You're not allowed to be up here."
In disbelief, the black woman was at a loss for words.  It can only be assumed her blood was boiling out of disrespect because she didn't say a word in response.  She was speechless.  The white woman just so happened to stand up and get off at the next stop.  It's unknown whether that was her actual destination or not.

If I asked you prior to telling this story whether you thought in 2012 this type of discrimination was still going on, chances are you'd probably say no as I would've, until now.  I am in utter shock and beyond taken aback by this woman's words.  How is it that in today's day and age, people can still be so self righteous, ignorant, and naive?  (for a lack of better words)  The answer is beyond me..

Tom P.