"If you've met one autistic person, you've met one autistic person." I don't know who said this originally, or even if it was used with regards to autism when it was said first. One can replace the word autistic with any other word describing a group of people. It makes perfect sense.
In the light of this, it always amazes me when somebody says that they know an autistic person, and then proceed to explain that they are like this, they do that, they are not capable of this and that, they always..., and so forth. It happens quite often. I have even had people question my diagnosis because I am not exactly like the other autistic person/s they know.
Sure, we have many things in common, that is why we are labeled autistic. For example, most of us have sensory processing issues (and some don't). Most of us have difficulty with eye contact. But these things present differently in all of us. We are unique, just like people who are not autistic. I do not like being thrown into the box labeled 'THEY'.