Humans aren't broadcasting into space with any pre-EM technologies. It's not so much that we don't care about less-advanced civilizations, but that broadcasting in a way that life forms could see/hear without electronic sensors would be many orders of magnitude less efficient for us. It's simply impractical.

Maybe there's another form of communication we haven't discovered yet that's so much faster and more efficient (like Star Trek's "subspace") that everybody else in the galaxy uses that instead. For them to send radio waves to Earth might be like us pointing Morse lamps at Alpha Centauri.

Trying to detect alien life by scanning the EM spectrum sure is inefficient. Maybe it's the best we can do, but if there were something better, I could totally see why we'd abandon plain old radio waves.