ancient man had love in bucketloads for his own tribe, the suffering of which he could not tolerate, particularly if it could be alleviated by conquering and destroying those who were not his own and taking what they had for what was perceived to be a greater good. It is the way it was, and the way it still is.
So, evolution DOESN' T explain our issue with the suffering of others or animlas, just the suffering of those we "know" ?
I am sure ancient man was NOT happy and cried "not fair" whenever something "unloving" was done to him too, wonder why since there was NO REASOn why He shoudl think that it was "unfair".
Personally I think that evolution DOES play a role in our compassion and love, I just don't think that it is the ONLY thing.
Evolution is what we go through when exposed to "enviromental changes" ( simplified yes, but bare with me)and we evolved when exposed to the environmental changes that was Love, compassion and a "higher moral".