The fact that most surprised me here is that social and humanistic topics, such as history, literature, religion, films and music are often special interests. I HATED these subjects at school.
I think you need to look at the reason for the special interest, rather than what the special interest actually is.
For example, a couple of mine are languages and music. In the case of music, basically, it's a stim. It also helps me feel calm feel good, helps regulate my emotions. I also enjoy collecting listening data and statistics, and trying out new music. It's something that I can lose myself fin for a while, and I feel a strong compulsion to do so. Collecting data, writing metadata and building up a music database also serves an innate need to organise and catalogue.
Languages: these started as fascinations for other countries, other places and cultures, and before I knew I was on the spectrum. They are a kind of escapism, wanting to emerse myself in a different culture, language, etc. They language ones have one thing in common: they started at times when I was under a lot of strain, down and depressed.
So apart from being interesting hobbies, they have a trigger and serve a function, and both the trigger and the function they serve are in some way related to autism, and it really doesn't matter what the actual special interest is, whether it be sports or languages or maths or dinosaurs, you will find that in autistic people, they serve a same or similar purpose.
Many people here feel this way about sports - it very much depends on the individual. The spectrum is very broad and is influenced by many factors - environment, genes, personality, etc. So although autistic people will have many traits in common, you get a very large variation in individual personalities and traits - as indeed you get with people in general.