Quite the oppose.
It tells us that intelligence and consciousness is so rare and valuable in the universe that other entities treasure and nurture it.
According to the film, we are the children of the (alien) gods. What can be more important than that?
Brilliant film yes. I would agree about it portraying Man as a minor player.
My take:
I've always viewed it as being about technological development and the potential isolation of people when engaging with technologies.
The monolith is first seen by the apes, then finally by Dave at his deathbed. First nothing is known (the apes don't understand what it is); then omniscience is achieved (Dave knows what it is). That is, the monolith is omniscience. The last thing is discovered at Jupiter and there is nothing much to talk about. Man's story is over.
Maybe the star gate sequence is the terror of Dave realising what this means.
2001: A Space Odyssey is the kind of film I almost comprehend but it's slightly out of reach. I don't think it has anything to do with aliens.
I think you're both right!
The
ahem Overlords behind the monoliths are looking for intelligence to harvest and shepherd to... umm... the next level.
But:
The vastness and
ennui (
@Karmacoma 
) makes man (humankind)
per se look pretty small and insignificant.
The match cut cut from the man-ape throwing the bone to the orbiting satellite (indeed, per Clarke's after-the-fact novel, it's presumably an orbiting nuclear weapon), besides being one of the coolest motion picture scenes ever burned into film,
makes the point, I think, that
all of mankind's history (which is what the movie skips over in
a split second) a) is steeped in death, or at least aggression and b) in the Universal sense,
doesn't amount to much isn't worth much screen time nor, by extension, much of a second thought. In the great scheme of things, it's just the tedious backstory to
breaking free of Earth's bonds.
But, yeah, we reached the moon, so (and again per Clarke's novel) we deserve(d) a promotion.
The promotion.
Two semi-on-point (i.e., pretty good, for
me 
) asides:
1)
2001 (or at least the TMA-1 business) was based on a Clarke short story called
The Sentinel.
2) For my money, Clarke's first novel,
Childhood's End, covers roughly the same
Übermensch territory even better than
2001. It is my favorite SF novel, full stop, and indeed one of my favorite novels to this day (and I first read it
a long time ago).
"The stars are not for man".
) whilst trying to remove same from the micronauts'submarine machine thingy? I used it as an intro slide to talk about the glycobiology of immunoglobulins. I mean... I would, right?
