Of course the cessation of human activities, such as the extraction and combustion of fossil fuels, that would accompany the disappearance of all that human biomass would be a boon to the biosphere.
It's like you're trying to impress everyone with your indifference to humanity, as though cultural insensitivity is somehow a corollary of scientific knowledge. The whole point of us becoming more enlightened (in both the sciences AND the humanities) over the last four centuries was to make us MORE sensitive to human culture, and more willing to make sacrifices for, and exhibit altruism towards people who aren't immediate family members, aren't from our 'tribe', or aren't even born yet. Eventually that altruism may even extend to the biosphere and your beloved algae. Obviously it's a work in progress and we're facing severe difficulties at the moment, but I don't see how it helps anyone to say that we should just buzz off and leave Earth to the ants, nor do I believe that's E.O.Wilson's view; on the contrary he expresses great fondness for humanity in his latest novel "Anthill," and apparently believes our achievements are worth fighting for.
It would be one thing if we were having this discussion on an Earth First blog, but I'm amazed to see stuff like this on RC. Your audience includes highly educated people who have devoted their lives to complex intellectual, linguistic, and symbolic activities that are beyond the capacity of most humans, never mind ants. On RC in particular people are clearly focused on the struggle to save civilization--science included--to whatever extent that's still possible. I sincerely doubt they enjoy hearing that humanity is useless rubbish and that the sooner we disappear the better. I know I sure don't.