If you believe it's impossible to travel faster than the speed of light there's no paradox at all - with literally billions of potential Earths in the Universe it's highly likely there's advanced life forms on some of them, maybe thousands of them - to think the Earth is unique is the height of ego-centrism. Hell, there's strong evidence that the very first life forms here came from outer space - every precious metal on earth came here via meteors, conditions on earth were never capable of making silver, gold, platinum, iridium, etc.
The problem with speed of light travel is time dilation - a crew on a spacecraft traveling one light year away from earth would experience on year of life, but on earth a hundred years would have passed - you would travel to your future when you returned, but you cannot go back in time. Think about how long humans have been transmitting high strength TV/radio signals into the Milky Way - less than 100 yrs - so no planets > 100 light years away could hear our signals, and most stars/planets are WAY further from us than that - same thing in reverse - we're too far away from the closest planet with a highly evolved life form to hear their broadcasts.
We have not been visited by ET's unless they've miraculously managed to figure out how to generate worm holes on command.