Yes, a lot of us more possessive about our things.
There are a few reasons of this. The most common of these reasons that most allistics will tell you is that we have reduced empathy and that prevents us from understanding the importance of sharing.
Of course, that is true for some of us, but it is hardly a universal thing. There are many other reasons why we may be possessive.
First, we often have a very strong sense of right and wrong. This comes from rules that we internalize very strongly, and tend to take as absolutes. These do not always reflect what the rest of society sees as right and wrong.
When kids grow up there is a normal phase where they come to understand that you do not touch others’ belongings without their permission. A lot of us internalize that as an absolute. It is a rule, you do not break it, full stop.
For others, it has to do with controlling our sensory environment. Everything has a place and should be in its place. Disrupting anything in that environment is disrupting out personal space that we rely on for sensory management.
Yet another concern many autistics have expressed is a heavy reliance on visual memory. Specifically, when you put something down you take a mental snapshot of where that item is. When someone touches that item, there is stronger emotion involved because they are touching your stuff, and you get a mental snapshot of that person touching your stuff. That replaces the snapshot of where the item was set down.
Even if the item is returned to the correct place, picture in your head is not longer of where the item was placed, but rather that the item was touched without permission. When you go to look for the item you cannot find it because the mental image does not include the location of the item.
There are so many reasons that I have heard from autistics about why they don’t like people touching their things. The common thread among all of them is that other people messing with our stuff disrupts our ability to function.
And like, for most people that is no big deal. Most people can adapt. With our tendency towards rigid thinking, however, this can be an extremely disrupting force in our lives.
The examples I listed above are nowhere near exhaustive. There are many, many, other reasons why we might be possessive. As a general rule of thumb, when it comes to autistics, I tend to assume there is a reason for it and take it on face value that it is important.
You prevent a lot of issues by taking that approach.
I am very possessive with my stuff and it’s kinda funny to me that some people would think it’s because of lack of empathy when a big part of it is my hyperempathy, so basically the complete opposite