Hm I think the spam guard ate my last comment so I'll repeat:
I don't think the SH are really up to converting an unwilling humanity despite all their superiority they are fundamentally unwilling to be inconvenienced so humans only have to successfully argue their case by pointing out the probable mass suicides depicted in the alternate ending and that SH society might take some casualties, since they are almost completely risk averse even the possibility of losing a single ship might be enough to scare them off.
It's a bit like the world being unwilling to intervene in North Korea despite the overwhelming advantage, it's just not worth a single life lost to us.
Given the SH's willingness to self modify it would be easier to convince them to ratchet down their empathy for us to tolerable levels
This was an interesting story, though I wonder if the human capitulation either option offers is the only option - bluntly, the superhappys don't strike me as being that tough, even if their technology is higher and development is orders of magnitude faster than ours they are completely unwilling to accept suffering even if it comes through their own sense of empathy, all humans have to do is offer a credible threat of superhappy suffering and convince them to modify themselves not to care about our suffering. i.e. "We will resist you every step of the way thus maximizing our suffering, plus you cannot be 100% sure you'll be able to convert us without us inflicting at least some harm"
Bugger there's my original comment after all. Whoops.