I'm confused... news says guy died of a nut allergy. But peanuts are legumes.

Looked up peanuts. Despite its name not a nut. Not grown on trees but under the ground like peas or beans. So why are they not allergic to peas/beans? If you have a peanut allergy you are likely to be sensitive to Soy Beans too. All bread in shops has Soy flour in it now? Don't know why? But it does.
Maybe they are trying to get rid of us all.