> Telomerase ... is present in cells that can continue to divide indefinitely, like stem cells and tumors.
Your cells dividing indefinitely is not the opposite of aging, it's cancer. This is completely quackery.
No. As long as they divide on schedule in the amount they're supposed to, they're not cancer.
Dividing indefinitely is the opposite of aging at the cell level; aging at the whole-organism level has some other stuff to it. I think there's so much emphasis on the cell division clock because we know what it is.
Look at it this way: the Hayflick Limit on cellular replication limits act as a fail-safe in case other growth inhibition mechanisms fail. If a liver cell decides that it wants to be its own immortal organism but doesn't express telomerase, it won't get very far in its enterprise. The replication limit makes it more likely that we'll survive to reproductive age.
On the other hand, the Hayflick Limit kills us. Evolution doesn't care much about this side effect, but we do. If we can suppress cancer other ways --- or hell, even if we can't --- NOPing out the Hayflick Limit safety code is worthwhile.