Nice uses of metaphors in your explanation. I like it and agree with it.Here is my problem with this entire argument...
It's asking if there is a link between oranges and grapefruits. Of course there is. That doesn't mean they are the same thing. It also doesn't mean that just because you have an orange in your fridge someone can assume that you have grapefruits, enjoy grapefruits, or even know what one is. Most of my friends and fellows are NTs. An INTJ I know is bipolar.
The other issue is autism is a very fast growing area of diagnosis. Here are some other things to consider...
Most INTJs are men, and the rates of diagnosed autism (ASD) show it is more common in men/boys. So there is one 'odd' against 'us'.
ASD is still being studied. From actually malformities of the brain, to simple chemical imbalances, there are so many variables and research into cause and treatment it is insane. A few years ago, the awkward kid in class was just that. Awkward. Now he probably has an ASD.
My brother actually has been diagnosed with aspergers. He is a text-book INTJ. I am an INTJ. Does that mean I have aspergers? He got three opinions, each confirmed the others diagnosis. I went to the same. Not aspergers. So there is a 50/50 rate right there for ya. Combine that with a mostly male INTJ population of that type, combined with the previous factoid, and yeah, it's a higher rate. But a higher rate of a smaller sample.
Aspergers, from dealing with my brother, is more than simply being socially awkward and loving technological stuff.
And INTJ is more than being a dark-humored asshole.
Not all citrus fruits are grapefruits, not all birds that can swim are ducks.
This was all discussed from a previous thread, and it was proven soundly there is no direct correlation other than statistics, which is a tricky beast to bet on alone.