Whether they're there or not, SETI is not finding any evidence, hence the "great silence".

There are a couple of possibilities that come to mind. SETI is looking for patterned electromagnetic radiation - maybe they don't do that (hey, we do that too, with "spread spectrum" communications) - maybe they're from far enough away that their spillover radiation hasn't gotten to us yet (light is fast, but not all *that* fast) - and, given the speed of light making it useless for interstellar communication, maybe they aren't using electromagnetics at all.

I'd love to believe they're out there, too. I'd also love to believe they're benign - but that's a different conversation.