'I once joked I was going to write a dissertation on "Tea as an instrument of oppression". '
I feel your pain. I don't drink tea or coffee and I can confirm that having hot drinks forced upon you, and being made to feel like a freak for not wanting to get involved, does not feel at all pleasant 
I agree with other posters that it is utterly jeffing pathetic that this needs explaining at all, but I do like the analogy.
I also quite like the 'Downs/Norway' thing. It can be used to explain a parent's response and feelings about their child being diagnosed with any additional need. In a nutshell, becoming a parent is like planning a trip to Italy - you learn some Italian, you check out the weather forecast for Italy, you find out what Italian sights you want to visit, you get all geared up for Italy. Finding out that your child has additional needs is like discovering that your Italy-bound flight has actually landed in Norway. This is not what you were expecting - the weather is different, the language is different, the food is different, everything is different. Its a huge shock - you feel disorientated, angry, sad, let down etc. But over time, you can get used to it and find out that its also possible to have a nice time in Norway, even though its not where you thought you would end up.
I'm not a parent but I do work with children with additional needs, and this analogy has helped me to try to understand some of the shock parents may feel when their child turns out to be so different to the child they thought they were going to have