Then you have to ask, why are they mimicking us? What is it about us that is worth mimicking?
Like, you can boil down a lot of this game to "Why humans?" It's not asking if the androids and machines are humans, but instead why they mimic us instead, sometimes in incredibly clumsy ways. Why do they look at us to define a purpose?
I'll tell you why I care, it's because in their exploration of us they created communities, and in its most basic form they found a purpose through each other. That's why I was incredibly saddened to see the circus machines reduced to zombies, why it's sad to see the forest machines enraged about losing their king, and Pascal destroyed from losing the community he himself built up.
It's also why I'm saddened for the androids. I knew all too well what it meant to lose god. How I have to face my gradual loss of a guiding stone, the nights I spent wondering what my brief 80 or so years amounts to in a universe that will span infinitely more. Look at how many societies around the world formed around religion to find a purpose for themselves in life. If you lose that guiding stone that tells you about what your life's meaning is, how would you deal with the loss? Or is it simply better to follow a lie blindly? Then why keep fighting in the name of a lie? Is that sense of purpose worth the bloodshed? Even now we have people fighting in the name of god, and the game asks us how truly senseless it is. The android's desperation for a god, to the point of being willing to sacrifice hundreds if not thousands to perpetuate a lie and a holy war where they can mindlessly kill and die because it's a purpose that exist as long as that lie is still believed, is truly sad to me.
It's the reason why it's sad to see 9S go on a rampage once he loses his only emotional anchor he has in his life, 2B. Why I care that 2B could only be near to the person she loves by having to forcibly erase him continuously, and why I care that 9S subconsciously allowed it because it's the only way he can break away from his own feelings of isolation, while his resentment slowly builds to a breaking point too. 2 androids that need each other to the point of desperation, and they are willing to bear the hurt for their brief moments of bliss without having to consider their horrifying circumstances. They found something they can cling on to this world other than a god they know doesn't exist. I care deeply because I'm a sucker for such tragedies.
And it's why I care about how Ending E ended the way it did. Why I care about the messages encouraging us not to give up even though for the past few hours we've been asked repeatedly if there really is a purpose to this world. Why I care that there are people willing to sacrifice everything (for the game anyway

) in order for us to create this sense of community of just wanting to see a goddamn happy ending in a yoko taro game, because we truly value the need to link for a common cause.
It asks us "Why humanity?" and in the end it tells us that we don't need an answer, but really, while we may not have a god or a true purpose, we do it anyway because we still define ourselves by the need to to connect to people surrounding us, that it is ultimately up to us to find our own true purpose, and that might just be all the answers that we need. Because we as humans really do try to cling onto dogmas with a predefined purpose instead of searching ourselves. We really do.
All of these is laid out pretty well for me by the game.