Read the Label
I can see the concern. But if there is any truth to the label, it also has a significant benefit.
When I'm volunteering with disabled kids, I always want to know what disability they've been diagnosed with. Let me use S for an example of why. S is obviously disabled - she says only short repetitive phrases with poor pronunciation, she has a noticeably odd gait, her mannerisms are very unusual, and she does unusual things (eg getting into your face and then exclaiming a noncommunitative 'go home', or walking into people and things as if she didn't see them). I could, of course, just leave it at that. Who needs to label S? She's just S, obviously unusual and very recognizable (chances are if you've met S, you know who I'm talking about).
Well, S has Rett Syndrome. And given my knowledge about Rett Syndrome, this label tells me something important that I may not otherwise have guessed - S has severe motor apraxia. This is a higher-level motor disorder that impacts the connection between movement and intention. She will often want to do a movement but be unable to start it. In addition, certain cues can make her do certain movements whether or not she wants to do them.
This means several things. Firstly, it means I don't need to invoke a cognitive explanation for something that could be a motor problem, such as her repetitive speech or her walking into things, which raises the possibility that she might be a lot smarter than anyone has guessed. Secondly, it means that when I try to communicate with her I have to do a guessing game - did she intend to do that or was it automatic? And thirdly, it means that I can help her do things she can't do independently, by giving her the right cues. If cued properly, she could partially dress herself, for example. I'd do half the movement for putting her clothes on, and then wait and see if she finished the job. And sometimes she did.
Does my use of labels mean not recognizing individuals? Certainly not. I have worked with many children with the label of autism. Each was distinct, each had their own way of relating to the world. The autism label helped to guide me, giving me hints about reasons for their behavior (probably not attention-seeking or manipulative, probably related to the sensory environment, dislike of change, or motor planning issues, etc) but each individual still has their own quirks. I briefly met another girl with Rett Syndrome, and she was very different from S (mainly a lot lower functioning, as she was in a wheelchair and had no speech or self-care skills).
But the individuality of these people does not negate the benefit of labeling them. All autistic kids are unique, but I have yet to see an autistic kid misbehave to get attention - something many Down Syndrome kids I've worked with have done. Most of the autistic kids I met would react adversely to a noisy environment, though I did meet a few who were fine with it. Many had problems if we changed their routine, although this ranged from aggression, self-injury and screaming at being in the wrong change room to simply seeming confused and less capable than usual in an environment where we did a different thing every day.
And with regards to myself, how I feel about my own label of autism? Well, before I knew about autism, I had many experiences that I lacked the framework to name, explain and acknowledge. I experienced sensory overload, but with no idea that it was sensory overload rather than just being picky and demanding. I felt that I was lazy because sometimes I could do things and other times I couldn't. I assumed (since my sex education classes assumed) that I would experience sexual desire, and mistook many non-sexual feelings for sexual during my early teens. I thought I was stupid, and when other kids failed to understand things that seemed obvious to me, I concluded that they were even dumber - completely failing to notice that I'd decided my entire class was stupid!
Finding out about autism has given me a framework to recognize those things about myself. It's also taught me that I can't just 'try harder' and expect to get results - I need to try differently. And most importantly, it's eased my loneliness. I now know how to find people who think like me, by looking for the label of autism. This was one big motivation in starting to work with autistic kids, because I feel less lonely when I spend time with a kid like me. And even if they're lower functioning than me, they'll have things in common with me that I don't have in common with NTs.
So read the label. It'll tell you something important about the person, even though it won't tell you everything.