You're not alone in thinking that, and there are some studies which seem to agree.
Fans of GURPS, or anyone looking to hear it in action should check out the podcast "the film reroll" (if you haven't already). They play through films as RPGs using GURPS and it's fantastic! They even had the creator of GURPS on once as one of many people playing Leonard in Momento. Also, there are absolutely no adverts.
Before you even mentioned autism I was thinking "I wonder if they might be autistic", so with that in mind you may want to look up the double empathy problem. Basically, multiple studies have shown that autistic people find it easier to empathise with other autistic people and harder to empathise with allistic (non-autistic) people, whilst the exact opposite is true for allistic people. Importantly, contrary to what many previously believed, there is no difference in the overall level of empathy, it's more a matter of compatibility.
The point being, that the people in this thread who have implied that you lack empathy are probably wrong, and your above comment would seem to agree with this.
I haven't done too much research into ADHD (which I don't have) but if it's anything like autism (which I do have) then it may well be that it's just massively under diagnosed in people who aren't rich, white, boys. I know they aren't the same but that's certainly the case for autism, and there is a high rate of co-occurrence between the two.