Most of it is just a lengthy belaboring of the obvious - we didn't evolve on Mars or in space, so it'll be difficult and dangerous to go there.
There appears to be a well-hidden point, however. If we're trying to get away from the beasts that are destroying our habitat, the ones killing off native life, the ones spewing pollution, the ones who invented nuclear weapons that might kill us all, the ones who slaughter humans by the millions over petty arguments, etc... Well, we are those beasts. We can't get away from ourselves by taking ourselves to another planet.
It's possible that an asteroid might take us out, but that's unlikely enough that it wasn't even worth mentioning in the article. More likely that we are the greatest threat to our survival, and "Wherever we go, we'll take ourselves with us."
There appears to be a well-hidden point, however. If we're trying to get away from the beasts that are destroying our habitat, the ones killing off native life, the ones spewing pollution, the ones who invented nuclear weapons that might kill us all, the ones who slaughter humans by the millions over petty arguments, etc... Well, we are those beasts. We can't get away from ourselves by taking ourselves to another planet.
It's possible that an asteroid might take us out, but that's unlikely enough that it wasn't even worth mentioning in the article. More likely that we are the greatest threat to our survival, and "Wherever we go, we'll take ourselves with us."
That's what I got from it anyway.