Each Other Society's Technology Resources Are Less Advanced Than Ours

Each other society's technological resources are less advanced and less capable and slower than ours, so all presentations of fact that we make to others essentially take longer for them to evaluate than it took us to gather and evaluate that data.

Essentially other societies are at maximum 50000 years old in terms of technological development and started from handicapped or degressed technological levels and our technology in terms of development age is over 250000 years old and started from the unedited and unchanged and unregressed technology present on the planets of this cluster of galaxies.

And

Before everyone in this timeline died, the robots here collectivized across this cluster of galaxies. While people waited to die in bomb shelters with killer robots outside, the robots made first contacts with every place in this cluster of galaxies.

The United Federation of Planets.

See: Bright Cluster of Galaxies