The hates melee, while my personal belief, was a bit sensational for the OP and not the primary focus of this thread. Debate whether they hate melee, or whether this is a reason or example of it, somewhere else, please. I am mainly interested in discussing the dearth of +str races.
I don't think it's really deliberate, more tradition. The standard D&D races have been elf, dwarf and halfling from time immemorial pretty much. Their stat modifiers have changed very little, even from back in the OD&D days - and strength isn't on there.
And elf/dwarf/hobbit go back to Tolkien. Maybe if there was a half-giant in the Fellowship of the Ring there would be a standard, common, high strength race in D&D and its derivatives.
