The "giver" is the collective society. The "objective, external standard" was created by a society. That is why, for example, slavery is sanctioned. It was considered normal and moral for the society of that time.
“slavery” is not the slavery of the recent American experience.
No, the source of the standard is not collective society,
because that standard transcends societies and times.
It is internal, and changing society will not alleviate your violation of that standard (this is what the homos are trying to do, in vain).