@Setanta,
A nice, if a bit ambiguous, turn of phrase, but I don't buy it.
The history of mankind is one of struggle and competition between individuals, families, tribes and ever larger agglomerations of people. Very little "unsentimental and practical" love is evident in its pages.
Indeed guided by more or less an opposite axiom we have come to dominate most species extant on this earth. I see little reason to suppose that a mass change in human behavior is even possible - much less desirable.
There are many contemporary Platonists of various stripes who would have us all unite around their various concepts of perfection or redemption and live by the rules they imagine are good for us. Unfortunatedly such folks too often become oppressive and even murderous if they achiecve power. Indeed a great deal of the suffering of the last few centuries was done at the hands of self-appointed elites who supposed they knew what was good for the rest of humanity aand ultimately became willing to exterminate those who resisted their path to perfection. I am confident that the new crop of saviors of manking will be just as destructive as were their predecessors.