[weego]

"If such things existed intelligent life would have used them to reach us."

For what reason would we be a magnet for everything out there to have to come visit us (the assumption being that if they don't visit us it can't be possible because we are somehow too important to ignore)? It's a rather flawed basis for an argument.

Our communications out don't speed up getting to them because their ability to get to us has. There is no reason to assume anyone knows we exist yet.

[Retric]

The assumption is if you have a FTL civilization you vary quickly grow to the point where you go just abut everywhere you can reach with FTL travel, unless something else was already there to defend it. Extinction becomes really hard when individuals are being sent out faster than just about anything that could catch them.