It depends on the context. In some cases the person might be taunting you to defend your position, or simply trying to avoid some subject.
But let's say that the person says this out of the blue, and is proselytising this view that human rights should be opposed. In this situation I believe that the person thinks that they benefit from denying human rights to other people; it's mostly selfish. (And worse, stupid - the person will be likely in the short end of the stick.)
I won't address everything because it's a lot of text, OK? (I did read it though.)
I think that it's more accurate to say that reasoning is a "tool" that you use to handle knowledge. And sure, without knowledge you aren't able to use reasoning, but sometimes even with knowledge you aren't able to do it either - we brainfart, fall for fallacies, etc.
Another detail is that ignorance is far more specific - a person isn't just "ignorant", but "ignorant on a certain matter". For example it's perfectly possible to be ignorant on quantum mechanics while being informed on knitting, or vice versa. In the meantime intelligence - and thus stupidity - is split into only a handful of categories (verbal, abstract, social, etc.).
They'd consider us ignorant. At least if following the distinction that I'm emphasising.
Not necessarily reducing it but I get your point, given that I think that it's simply easier to talk about ignorance and stupidity as behaviour than as something inside our "minds" (whatever "mind" means). And in both cases it's behaviour that we all engage; some more than others, but we all do.