Yes, I get that, but at what point do you start considering future children over the current children? Accelerationists are not deontologists, they are consequentialists. A child lost now is valued against the amount of children saved at some calculated point later.
No, the best way to convince an accelerationist that accelerationism is not the right play is to show that there will be no decently positive outcome. Which I'm inclined to agree with, since I can only imagine the continual election of populist figures such as Trump will only increase the divide between voters of the two parties. This'll create more violence, possibly destabilize the US, and could destabilize large parts of the western world due to policy, military vacuum, and emboldening of alt right groups. Now measure all those consequences against the possibility of an improvement in the political system and multiply that by likelihood. This, to me, seems like a very low gain, for the high likelihood of increased losses. So it should be preferable for accelerationists to go with Biden, since he's likely to bring about accelerationists goals too, but with less risk, but much slower.
Regardless, it doesn't change the fact that it's incredibly hard to vote earnestly rather than strategically.