It is obvious that it is about friendship, decency and loyalty to our own species.
The science fiction is secondary.
I like your formulation save the last bit in the opening clause. Loyalty as in racial chauvinism or an implication of exceptionalism? While I know many have pointed out that in its execution, the franchise more than slightly evokes a sense of Empire Americana in the stars, I don't think I see that a core loyalty to humanity is what the overarching vision of Trek through the years has tried to communicate. Needless to say, it would seem to run counter to the IDIC ethos. I think such an emphasis more accurately reflects the Terran Empire's conceptual basis.