Imagine you were off-planet, as a member of a crew doing scheduled work on an asteroid. Imagine something happened while you were away and came back to discover everyone had died for no apparent reason. Imagine every individual in every species close to yours, like chimpanzees, gorillas and orangutans, had been wiped out as well. Imagine the only surviving primates were marmosets, capuchins, howlers and a few other small monkeys. Imagine a few among you were brave enough and descended to attempt to figure out what had happened. Imagine they all died within minutes of landing.
We had no choice but to flee back to the asteroid and freeze ourselves there for a time, to allow the plague, or whatever it was, to pass and let life move on; we expected to return to find a new intelligent species that had arisen from any of our surviving little cousins; we expected to meet them as brothers, or at the very least to guide them into forming a new advanced civilization, like ours was.
What have we found instead? The world overrun by apes. Our little kin differentiated into dozens of species, each and every one of them a caricature of their ancestry, yet still sporting minuscule, degraded samples of the features that made US great; their limited muscle flexibility, poor skin changing ability, reduced intelligence, small number of tentacles, lackluster three hearts, absurdly short lifespans spent playing the role of small predators... all come off as an outright insult to what WE were.
It's clear Earth doesn't want us back, so we won't have anything to do with it, either.