Every SETI search ever conducted adds up to sampling a hot tub's worth of an ocean, so finding nothing tells us nothing.

And what they found was if that search space, if the sky is an ocean and you're looking for fish, how much of the ocean have we looked at, and it turns out to be a hot tub. That's how much of the ocean that we've looked up. We've dragged a hot tub's worth of ocean water up and there was no fish in it