"But it’s a lie. Humanity will never colonize space. We are not separate or separable from this planet in that way."
It depends on the 'we' that we're talking about. If we're referring to biological & presumably intelligent organisms who are pretty the same as they have been for thousands of years, then space and vaccums will never be safe enough, transportation will probably never be fast enough, and shielding won't protect us from mostly unknown territories.
But if our physiques are augmented or transformed with non-biological parts, then safe travel becomes possible. It might not even be 'travel' in the normal sense of the word.
At any rate, there are more deserving intiatives, more terrestrial & important & humanitarian than trying to escape the environment that we fucked up, while trusting the builders to cut us in on the deal.