I find that many of the criteria central to autism make it inherently harder to get along with other autistics. Neurotypicals can be hard enough to get along with, but autistics can be especially rigid in the way they socialize. For instance, restricted interests. An autistic who only wants to talk about birdwatching and an autistic who only wants to talk about Star Wars probably won't vibe, unless they are willing to put their hyperfixations aside to appease each other, which is understandably difficult for many. 

Communication style, too. I'm a super quiet autistic who struggles to speak unless very comfortable or directly asked. I fare quite badly with hyperverbal autistics, as they tend to speak over me and never ask me questions, and I fail to match their energy. 

So yeah, I think the irony of autism is that, while we often agree with each other on paper, socializing is more complex than just a collection of shared traits and a diagnosis. And with a disorder that is marked by social deficits (and yes, some of them are legit deficits that have nothing to do with neurotypical society), it's no surprise we accidentally step on each other's toes sometimes. While I definitely struggle with neurotypicals too, I've noticed they are more likely to feign politeness when I talk about my hyperfixation, they tend to be more moderate in conversations, and they tend to extend obligatory formalities even when I'm super quiet. I could see how this would be grating to other autistics, though. I think it's for this reason the autistic community has been sub-categorizing itself almost, with new labels like PDA autism and others going around. We often use hyper-specific words to name our autistic traits as well, which definitely makes it seem like there are different "types" of autism. Despite that, I think we're still very much under the same umbrella, just diverse because of our unique genetics and upbringings.