Diamond Lights
Alan Hutton
may well be, it may be that Human's are the furthest along the evolution chain and therefore the species most likely to either wipe itself out or build interstellar travel and wipe out other species who may post a threat. From WIKI:What's the counter point to the second one. Heard that one repeatedly and it seems like a plausible factor.
A species might undertake such extermination out of expansionist motives, greed, paranoia, or aggression. In 1981, cosmologist Edward Harrison argued that such behavior would be an act of prudence: an intelligent species that has overcome its own self-destructive tendencies might view any other species bent on galactic expansion as a threat.[85] It has also been suggested that a successful alien species would be a superpredator, as are humans.[86][87]:112 Another possibility invokes the "tragedy of the commons" and the anthropic principle: the first lifeform to achieve interstellar travel will necessarily (even if unintentionally) prevent competitors from arising, and humans simply happen to be first