It's almost definitional of IR in fact, but not quite. Waves which are relaxed enough to pass through ordinary matter, but interact in interesting ways with me

It's almost definitional of IR in fact, but not quite. Waves which are relaxed enough to pass through ordinary matter, but interact in interesting ways with metals and other electron clouds, we call radio. Microwaves start out doing this: usefully, they spin water molecules around, hence microwave ovens. What we call microwaves 'bottom out' on not doing so, it's a useful but somewhat artificial category which I would split between radio and IR if you gave me the gavel. Unlike visible, which is 'visible' because it has distinct properties.