"Um, you realize that passive shielding is in fact legal? By the above ridiculous argument, it should not be."
Spectrum licenses apply to transmitters only. It kinda makes sense if you think about it.
On the contrary, you've offered my own argument why it doesn't make sense. Given that I can passively shield my building, you will have little trouble realizing that inside an RF quiet room I am also free to generate as much RF as I please on any frequency I like. If you ponder that very carefully, you will realize that restricting emission is not sensible. Restricting RFI is what makes sense.
If you reach that epiphany, you will realize that the question boils down to this: should you be entitled to protection from RFI on my private property? After you discover you are unable to justify a positive answer, you will reply, "Say what you want, jamming is illegal." You might even bold or capitalize illegal, just to prove your point even more.