They're not so much cheering, as living in their own little world.
This is a frailty of humans in general, because we can spin a stick, we believe we are the greatest heroes on earth, when in fact we're but a small part of what makes earth work.
Cancer cells must be realllllly full of themselves, LOOK how fast we're growing, and look how much energy we consume, Irrespective of the control mechanisms of "The body."
Then the host dies.
Animal Agriculture is that cancer.