Maybe the cosmological constant is fine tuned for life not destroying itself. We humans have developed into organisms that are able consume every resources available to us, leaving destruction behind. As I understand the slight positive value is linked to the increasing expansion of the universe. Were it negative, the universe would collapse on itself. As the article also point out, there should be a sufficient time span for life to exist.
In the far future humans may be able to make interstellar travel. The amount of energy required is enormous, in planet or even star sized quantities. So if we are able to harvest this energy, matter will be a non-renewable resource that we can consume and eventually destroy our galaxy. If other galaxies were within reach of our spaceships, we could simply move to another one. (This is basically the same idea that we can move to Mars when we have destroyed Earth.)
Hence, maybe the cosmological constant is exactly the right value for life to exist, but leave galaxies out of reach of each other so life can only destroy one galaxy, containing destruction to very small areas of the universe. Assuming life in a large fraction of galaxies, some of this life would be smart enough or to little advanced to destroy their own galaxy, making sure life exist throughout the lifespan of the universe.