Is it ignorance or discrimination?

On PTT's WomenTalk forum, a woman who lives in Britain brought up some scenarios that she personally experienced with her coworkers. Read the article, and then let's talk about the cases she brought up!

I think we have to first have to define the difference between prejudice and racism. Prejudice — holding negative beleifs about a group of individuals, and assuming individuals share these characteristics
Racism — the social mechanisms (prejudice, disadvantaging, outright attacks) by which social power is differentiated for groups, and through the dissemination of which a group gains and maintains social dominance

Scenario 1: “Whatever”
Is it discrimination that someone should not distinguish between Taiwan and China, or only politics?
If sb can’t tell the difference between Chinese, Japanese, Korean, is that racism? Unfamiliarity? Laziness?
Is it the same or different situation if, for instance, a Taiwanese person would be like, “Oh, Polish, Russian, it’s about the same?”
Would a Taiwanese person say that though?

Scenario 2: “Chopsticks”
What are the assumptions behind this kind of question:
—personal cultural preference?
—level of exposure to outside cultures?
—competence/incompetence in cultural norms?
Do assumptions/intentions behind actions matter?
Or the feelings resulting from the actions?
Which matters more?

Scenario 3: “Ping Pong”
Is assuming a behaviour or predilection discriminatory? Or just ignorant?
Is using a cultural stereotype to make fun of sb just ignorant or actively hateful?
Are all cultural stereotypes equally harmful? Are some okay?

Scenario 4: “Drop a Spoon”
When is it okay to tell jokes that make fun of other peoples’ culture or other cultural groups’ behaviour?
When people make assumptions and bring up topics like this that make you uncomfortable, when is it better to challenge it, and when is it better to let it go? (hint: your answer is going to be influenced by the assumptions of your current cultural millieu)
Also, if you go about challenging what is said, what is the best way to challenge the assumptions of the people around you?

Finally, let's discuss this quote:
Prejudice is an emotional commitment to ignorance.
—Nathan Rutstein