You're right--but this applies to disabled people too. Depending on the country to live in, it can be really difficult to be properly accommodated if you are disabled. The Affordable Care Act is constantly being jeopardized when we fight over different aspects of medical law. Just like any minority, disabled people have to contend with people speaking over them; with not being able to find accessible parking or get into buildings because they are made for able-bodied people; and in awful cases, where it isn't just that they're being ignored but they're actively being discriminated against, there may be lack of legislation to guarantee their safety or autonomy. In the US, where I'm speaking from, you can apply for disability, but that means that the government can take it away the second that you try to earn extra income for yourself. It's no coincidence that disability and poverty often go hand in hand. And that is something that statistically follows being a minority--if you are a small portion of the population that is facing challenges, that compounds other difficulties such as financial status.
So if I have one eye of different colors that makes me part of a minority?
then cancer people should be a minority too
The reason why these do not match up is because there is not active stigma and/or disrespect happening against these groups on a large, systemic scale. People with cancer are, if we don't get into individual financial/familial situations, given treatment and supported. People with an eye that is a different color do not have an adverse effect on their life unless there is a disease attached to it, making them blind, and then they are disabled.
Minorities face discrimination, and people who are disabled are not exempt from that. Among many, many other examples I could pull up, they were sent to death camps/executed along with other minorities in the Holocaust.
Your father may be strong but not everyone is your father.
Not everyone is her father, but also, not every person who is disabled is like you describe. Not all of them are the result of chronic illness or connected to chronic illness. Some people are amputees because of injuries. Some are born without limbs or with deformed limbs. Some have invisible disabilities. You cannot group them all in the same frame of "being ill." Just like any minority, whether it be ethnic, LGBT, whatever, there are a broad range of experiences within their community/communities. People who identify as Deaf instead of just deaf, for instance, have a broad set of communities with different cultures.
We're not saying you shouldn't show them empathy, but saying that all disability is a tragedy is really patronizing. Yes it affects their life, but discrimination is as much part of their battle as their condition itself. They can find it really patronizing to treat them like charity cases when many have adapted (or want us to give them legal resources and laws that make it easier to adapt!) to their condition and just want you to listen to their voices instead of speaking over them, because there ARE ways for them to live well, though not as easily as abled people, if you just listen to their requests and show them the same respect you would show an able-bodied person.
My mother is disabled and two of my best friends are, all in different ways. My mother needs a cane in order to walk; Friend A just needs to compensate with a limp but is also almost completely blind; and Friend B requires a motorized scooter/canes as her mobility aids. I didn't previously comment on this post because of the OP's wishes, but I have a lot of experience with knowing people with different types of disabilities.