The Jovian moons might be a better bet
When we have done a thorough survey of the rest of the worlds in this system
and haven't found anything resembling life, then we can start truly saying Earth
is the only life-friendly place, at least around here.
We have just barely started. Flying past some world at hundreds and thousands
of miles with a probe that is not designed to look for life is not a thorough survey.
That is the situation with most worlds around here.