I don't see how God existing would give humanity a point, at least God wouldn't necessarily give us a meaningful point.
The argument seems to be one of two things:
(1) a created thing has a purpose, therefore if humans are created they must have a purpose. However, if this is true there is no reason to think that purpose would necessarily be meaningful or desirable to created thing. E.g. Computers and domestic animals have purposes and are created. If by some freak accident either computers or domesticated animals were to become self aware in the human sense, it seems unlikely to me they'd find the "purpose" we've assigned them to be meaningful.
(2) an all powerful being can by it's nature create purpose. Again, there's not reason to think this purpose would necessarily be meaningful or desirable. Furthermore, this seems like just an appeal to authority. We live in a world with greater material powers than us already. The meanings and purposes created by these powers are often recognized as illegitimate.
Now you could state that all good, all powerful creator god would by necessity give humans a meaningful purpose. However, if that's true then that meaningful purpose is obscured to us just as the nature of God is obscured to us (this is self evident from all the religious & philosophical debate about this topic). And just as in an atheistic world, it'd be up to humans to develop/discover meaningful purpose thru reason and spiritual practice.
Adding God, imo, doesn't seem to help "humanity to have a point" in a pragmatic sense.
If you desire purpose, then the point of life is to find purpose. If you can't find purpose, then the point of life is to create purpose.
Most people do it by having a child. But that's the big one. Every little thing you choose to attempt for your own satisfaction or advancement, or to fulfill your values, every action of self-improvement; these are all ways to create purpose in your life.
The fact is, you're alive. Any attempt to live your life to its fullest is the pursuit of purpose for the sake of your own life.
"Purpose" is a human-created concept. All purpose is created by someone, and there's no reason you can't do the same.
If god is real, what is our purpose? To worship an egomaniac for eternity?
We could have a purpose given by God, but it's not guaranteed. I make things that have no purpose, so God could, too.
As someone who used to be religious, I find I feel there's actually more purpose to life without god. Like, if there is a god then presumably there must be a finite number of predetermined ways to find purpose. In the evangelical Christianity I was raised in, this usually took the forming of either "honoring God" by not having premarital sex or working to curtail the rights of others, or just having a big family.
But if we're on our own here, that means it's up to us 100% to figure out what will give our lives meaning, both individually and collectively as humans. I kinda like that myself.
Is there anything north of the north pole? Where does your lap go when you stand up? Some questions are malformed and don't have answers - I would count the question of "Is there a point to humanity?" among them. Sometimes we ask questions like "why does fire burn?" and answer it with, "well, at a certain temperature oxidizers react with chemicals to produce blah blah blah..." but that's not really an answer to why it's an answer to how. Some of these why questions are not possible to be answered.
If God is real, that doesn't mean humanity has a point. The Ultimate Being and maintainer of the universe may be more interested in the orbits of lifeless rocks and chemistry of stars given the fact that we don't see any other intelligent life out there in the universe. We may be an accidental side reaction in God's creation that It just doesn't care about given our puny lifespans and puny interests. It may also be that humanity has a point, but it's a point that we may consider evil (such as the Demiurge of gnostic Christianity).
If God is not real, then humanity may have no point. We just exist like everything else does and derive our own meaning. We may have a teleological point if God doesn't exist - in dialectical materialism it could be that the ultimate synthesis is that between Unconscious, Unthinking matter and Conscious, Purposeful matter (Mao's On Contradiction has a good bit at the end about dialectical materialism that expands to include Differentiation and Integration, Positive and Negative, etc.). We may have a purpose in lighting the dark of the universe and filling it with computronium and maximally produced consciousness.
