So tired of this meme. Humans are like a virus in the way that every species on the planet is like a virus. Look no further than invasive species to see that any form of life given the ability to expand it's population will do exactly that. The majority of species reach what we view as 'an equilibrium' because they run into the constraints of their environment on a scale small enough for us to make note of, but humans do the exact same thing; only our scale is the entire planet and we haven't run into the constraints yet. The moment humans were intelligent enough to form agriculture is the moment humans inherited this planet.
I totally agree with you here. Just saying that probably treating dolphins as people might not help (or be enough), considering that the size of planet would remain constant but we'll double our density soon.