I'm not religious because I have a lot of problems with the way religion often trivializes human experience. By the same token, I can't help but cringe when someone talks about humans being "bags of chemicals." It's not as if I prefer my dehumanization evidence-based. It's that I object to any worldview that degrades and dehumanizes us.
But how does it dehumanize us to notice what we're made of? If it dehumanizes a human to notice that he's made of biochemicals, does it derabbitize a rabbit to notice the same about the rabbit? Does it dediamondize a diamond to notice that it's made of carbon? Dehousize a house to notice that it's made of bricks?
I'm sure you can recognize the distinction between noticing what we're made of and defining ourselves as a collection of the chemicals that comprise the human body.
But who has? If I say that I am a collection of chemicals, I do not imply that I am interchangeable with any other collection of chemicals, that my properties are no more interesting or valuable than those of an equal weight of magnesium sulfate. And who does say or mean such a thing?