Considering that the moment echoes down, influencing people who don't even know what happened there, I don't think that's a defensible interpretation, to be honest. People who approach the location of the moment with no mindfulness at all are overwhelmed with a sense of importance.
I think it is defensible. I know the story is called "THE Moment" but I don't believe the story itself implies it is the ONLY moment in the universe. It is one of many, it's just this particular one is a human moment.
I agree with Davedoty's puzzlement, as the fact that the moment was not unique (which, indeed, is explicitly stated in the story) is not under attack by anyone, and is irrelevant to both Liminal's reading and Davedoty's criticism of that reading as being at odds with the story itself.
That said, the ending of the story makes it clear that while they are other moments, it is not the case that every time a species first leaves its planet a moment is created - indeed, the student godling at the end makes the same point. What makes this particular footprint so unique was that, unlike in other cases, the human race did not take a step back, but rather "jumped off". That's vague enough to support a lot of interpretations, but I think all of them must be based on the principle that the human race is somehow more special than others at the same position.
Also, and this didn't occur to me until now, this seems like a story in denial, given that the human race very much *did* take a step back in its space exploration after setting foot in the moon. At the most generous, it can be said that our next step into space in a tentative, cautious one. Now sure, in the timespan of millions of years it can be thought that the past 4.5 decades are insignificant, and maybe once we do restart our space programs in earnest then the current time period will be viewed as a small blip. *BUT* and this is crucial, the story argues that the universe chose to maintain that one spot in history because of the absence of any hesitation on the part of humanity. Whatever it is we did, we did not jump.
My distaste for the ending of this story grows the more I think of it.