That's what I meant by "effectively": Reflections, diffraction, and (moderate, i.e. think doors and windows, not walls) light obstacle penetration make some indoor reception possible, but the radio horizon remains the strong limiting factor.

That's even true for the L- and S-band; otherwise you wouldn't be able to use a cell phone in a windowless room, for example. (Much of what's commonly attributed to "object penetration" is actually mostly due to reflections and diffraction around obstacles.)