Obviously eliminating humans by violent means would be immoral, but I don't see the problem with individuals deciding not to sustain humanity as it exists now.
For example, if you want to replace all human labor by robots, a lot of people would be against that, because they fear being unemployed. But if you don't intend to leave those unemployed people without food and shelter, I don't see anything wrong with still pursuing that goal.
> If machines produce everything we need, the outcome will depend on how things are distributed. Everyone can enjoy a life of luxurious leisure if the machine-produced wealth is shared, or most people can end up miserably poor if the machine-owners successfully lobby against wealth redistribution. So far, the trend seems to be toward the second option, with technology driving ever-increasing inequality.
-- Stephen Hawking in a very lucid moment, https://www.reddit.com/r/science/comments/3nyn5i/science_ama...
Those who don't address that first, who cannot ENSURE that they're building a nuclear power plant and not an atom bomb, have no excuse.
Taking away peoples' roles and turning them into welfare recipients is not universally seen as a good thing. Many people get fulfillment from the work they do because feel like they contribute to society. Taking away their job and providing them food and shelter does not solve that problem.
You don't feel like you contribute to society when your job is easily obsolete/easily automated.
Many people got fulfillment from playing Chess, or Go, or weaving, or tilling a field with their own hands. Many, but fewer people, still enjoy doing these things today, although machines are better at it than them. Others have moved on to other ways of self-fulfillment.
If you oppose automation of activities people find fulfillment in, you should oppose game-playing AI much more than jobs being automated away. There are much fewer people that hate playing board games but have to do it anyway because it's the one skill they have that will put bread on the table.
An interesting hobby like Chess or Go by definition can't replace the need to be depended on and feel like you are contributing.