There are many many groups that have been discriminated against. Some based on ethnicity or varying concepts of race; some based on religion or other concepts of faith; some based on various aspects of sexuality.
And some based on various aspects of disability.
There are similarities and differences among these groups, but one big difference is that we are (partly) disabled by our disability, rather than by some outside force.
For example, the only reason a Black person could not be a professional baseball player (pre Jackie Robinson) was because of bigotry. However, the reason a blind person cannot be a professional baseball player is because he or she cannot see.
Now, of course, society can make particular disabilities more or less disabling - e.g in a society where few people read, dyslexia is not a problem. Putting ramps in building entrances makes being in a wheelchair less disabling, and so on.
Further, some people generalize that a person who is disabled in one way must be disabled in others. They assume that people in wheelchairs can't hear too well. They assume that learning disabled people can't think too well. I've been told that I can't be learning disabled if I am good at reading and math. I guess you can't be tall and thin.
Even further, some people exaggerate the effects of any particular disability - and neglect the role that accommodations can play.
And yet ....some people in the learning disability field prefer to use "learning difference". I do not. I am disabled. There are things most people can do easily that I can do only with great difficulty or not at all. Among other things: I get lost all the time. I remember faces very badly. I am very bad at estimating time. I am bad at reading body language and facial expression.
But does my disability define me? Only partly
I am learning disabled. I am a father. I am a husband, an atheist, a liberal, a statistician, a PhD, nearsighted, curly-haired and many other things - some more and some less important. TOGETHER they still only partly define me. Humans are complex.
That's a big difference between disabled people and other stigmatized people. What about similarities? One similarity is that we are all stigmatized and discriminated against. Because of that, I think we in the disabled community have much to learn from the struggles of other groups.
For one thing, we don't fight stigma by hiding.
We're here. We're weird. Get used to it.