Okay, in responding to this obvious tragedy . .
We should try and listen with an open heart, which is hard, hard work.
And respond briefly and matter-of-factly, perhaps like, people who are aspie tend to be logical (and killing a bunch of people who have nothing to do with nothing is anything but logical!)* And we probably don't even need to say this second part, but just let people pick up on this. And actually, a lot of our fellow citizens or at least enough of our fellow citizens are good on issues of nondiscrimation and we need to kind of bank on this.
* And even this might be arguing too much and we want to under-argue. Okay, 1 out of 100 or 1 out of 88 persons is on the autism spectrum. With a world population of 6 billion more or less that means approximately 60,000,000 persons on the autism spectrum. A group of 60 million, you're going to have some horrendously bad actions, sadly, probably, may not but only if you get reasonably lucky. A few tremendously bad actions does not reflect on the entire group.
I have read that a person who is schizophrenic is actually less likely to commit a crime than is a member of the general public, and actually the person with schizophrenia is more likely to be victimized. Now, one subcategory, persons who have paranoid schizphrenia are more likely to commit a crime but only marginally so. And thus, we come to the not very remarkable conclusion that we should treat people as individuals. And I think we do a very good thing in standing up for other people. We're not just selfishly standing up for ourselves. We're also standing up for other people who are different in different ways and saying, hey, let's not be automaticallly afraid of something which is different.