"No one wants to talk to us" is not a sufficient explanation. We need to be able to explain why we don't observe any stellar engineering. Assuming alien civilizations they either 1) can't make use of the most prominent energy sources around, 2) choose not to for some reason, or 3) we can't detect what they're doing.

1 and 2 don't make sense if you assume that there are many alien civilizations older and more advanced than us. 3 implies that we're fundamentally misunderstanding a lot about (astro)physics.