> dozens of cunning linguists and digital signal processing experts working on DEATHSTAR

Yes, you might be able to deduce the general nature of the program. But specific capabilities are what is important.

Conversely, would you rather have a sign in your front yard which says, "Attention Criminals - The people in this house have guns." or a sign which says, "Attention Criminals - Nobody in this house has a gun." ?

> pulsars, for example, are often observed around the 1-1.5 GHz range. (There's a hydrogen emission line at 1.5 GHz,...

Yes, but as you look at objects farther away, they are also moving away from us at higher speeds causing red shift in all their emissions. So the 7 meter (40MHz) signals originated at a much higher frequency.