All of our experiences with autism are valid. It doesn't matter if you're a person who has autism, a parent of a child with it, an Aspie or a teacher. Each experience you have is real and important, and it makes an impact on you.
The problem is that we have is a tendency to invalidate or question of the experiences of others. We say that because the other person hasn't been through a certain thing or done something, their experiences with autism mean less. Sometimes it's a parent saying to an Aspie something like "Well, you don't have real autism like my child so what you say doesn't matter". Other times, it's a person with autism saying, "You don't know what it's like to have autism, so how can you know anything about it?" I'm guilty of doing this. It becomes a holier-than-thou battle which no one ever wins.
We can't agree - and probably won't ever agree- on the most basic concepts of autism. What causes it, why, if it should be cured, how to deal with it, all of those things. Because we can't agree, we find every little thing to fight over and often end up telling others that for various reasons their view of what autism is like is wrong, that they don't know what autism is really like.
I'm going to be trying to give up my judgmental attitude toward others. I'd love for you to join me. We might not agree on a lot, but we all have experience with autism in some way. It's a part of all of us, and that unites us even in our great divides.