Highbloods would likely be detached from Lowbloods. Maybe thats where the treatment comes from?

Cause in the long term its likely to cause ALLOT more grief to all parties.....

Maybe that why they don't care about death or each other? Because their psychologicaly not care about the deaths of their close ones as they are likely to outlive them?

So perhaps heavy troll love is mild human friendship with benefits?