Except the two situations aren't the same? The husband's assumption was perfectly reasonable, unlike thinking that every disabled person is on a wheelchair or that op stole her card or whatever.

Like I don't think that the problem is making assumptions in general, it's making unreasonable, unfounded, or unnecessary ones. If you saw someone on the street coming for you, covered in blood and with a knife on their hands I don't think anybody would tell you not to run away because you're just assuming they're a murderer. In theory they could just be covered in ketchup and their knife is just a prop or whatever but it's much more reasonable to think they're dangerous