TBH I've not encountered too much of that response fortunately. Generally people fall into three camps: no real idea about either and find it hard to believe me as they assume it's rain man or that sweaty boy in class who never sat still; the "Oh yeah I have ADHD sometimes" crowd; and professionals who understand or at least admit they aren't qualified to know.
What I read a LOT of that doesn't really match my experience is that people experience them as separate conditions that "take turns" with a "today the ADHD is in charge, yesterday it was the autism". I don't experience things that way at all. They are both there the whole time. The environment (and other things) might mean I experience one more than another, but they're both there the whole time. At first glance you could say they are in conflict, but it doesn't feel that way to me, because they trigger emotions that coexist. So at no point do I feel like I'm tossing up which to address. Hard to explain.
Example the need for routine "vs" the drive for novelty/impulsivity. I don't experience that as a rational thing. It's not like I sit there and think "Hmmm, I'd like the same things, but at the same time I'd also like something completely different". The way I experience it is through emotional response, that is fear and restlessness, which both lead to anxiety. To me it doesn't feel like an either/or. They are both there the whole time. To some extent I am always compelled to ruminating on the past and trying to plan the future to avoid negative outcomes. And I am always feeling this discomfort that I should be seeking out something else, even when I'm doing something else. Neither can be resolved because there is no external state possible that will turn off that tendency in my brain, both are there the whole time. If it were the outside world doing this to me, it would be more either/or. But it's not the outside world causing this, it's not a response to the world, because they are both driven by my brain, so they are both there, all the time, and that's not a paradox at all.