I'm not a huge fan of 'narcissists' usage here. We really shouldn't be trying to pit neurodivergent people against each other or demonize people with a particular condition. Bullies would have been just fine.....sorry about the minor nitpick because I agree with OP's sentiment but still...

Keep in mind that if you don't think an official diagnosis will help you, it also isn't strictly necessary if you'd still like to consider yourself autistic. If it seems like autism is explaining the person you've been your whole life then you're almost certainly autistic!

Diagnosis is useful for getting disability benefits or certain accommodations but most of those accommodations are things you could get if you have other mental health conditions or neurodivergences that are less stigmatized in the workplace. Also once it is on your medical charts you may run into more issues with medical care. You want to be very careful about who you tell in the workplace because you'll likely get discriminated against and it really won't help in cases where you're likely getting discriminated against anyways (most workplace situations since most people discriminate against autistics). Yes I know discrimination based on disability is 'illegal' in most places but it is extremely hard to prove especially in certain parts of, say, the United States. Diagnosis would also get rid of the nagging thought of not being "really" autistic. It's up to you.

It's a roundabout way to mock neurodivergent people. People can flat out mock autistic traits and then be like "god redditors are the worst" and other people will agree. Of course, it's never about the people who say these things's use of reddit or their friends' use of reddit. It's not just reddit that this applies to, either. Or even neurodivergency. It can also be used more generally to be racist, homophobic, transphobic....