Hmmmmmm...
I guess that they are failing to take into account the fact that they are jamming it has significance? IE: *If* it wasn't doing or saying something that might be `tweaking' the Castro regimé then *why* would they bother to go to the effort to jam it? After all, while it is costing our side it is *also* costing their side and that cost isn't `peanuts'. And... Since they *are* jamming the broadcasts it probably causes any potential, or actual, loyalists or not, listeners in whatever moments the signals *may* sneak through, to have reason to wonder and maybe think a bit about the `what' and `why' it is being jammed by the Castro regimé.
Just an `Olde Fart's' 2¢ worth. {VBE GRIN!}