[XorNot]

Still a relatively slow way to get around. We have some co-factor here for "median time between alien contacts" which might be thousands of years. In which case they came, they saw, and the people who saw them remembered it as folk tales.

[scrumper]

"Speed" could be seen in terms of perceived time for distance covered. No reason with a robot-uploaded consciousness that you couldn't slow its perception of time such that travel between the stars becomes something comprehensible by a human-like mind. A bit like video game time acceleration, but real.

That doesn't address what happens to the visitees, but if that kind of slow-scale exploration becomes the default, then any civilizations on a similar level to the robot explorers would have technology and societal structures in place to support meaningful contact of that nature.