The trouble with the three-body problem

I started off loving this: the first couple of episodes were just brilliantly clever and although the kind of timescales aren't plausible for real three-body stellar systems, you can forgive them that.

Then it just dropped the ball by introducing magic: how do the aliens talk to us? Oh, right, they have superluminal communications technology. Which is magic, not science, and if it did exist would mean they could send information into the past and thus solve the prediction problem they have.

Oh, and it will take the aliens 400 years to get here. So why does anyone even care? Unmitigated climate change is going to have civilisation-ending effects in a century and we collectively are doing almost nothing about it because, apparently, we don't care about our children and grandchildren: why would we care that some aliens will arrive in 400 years to look over the wreckage of modern civilisation and think 'oops, that was a wasted trip'?

I mean, really.