How is one unit of account in the Bitcoin blockchain ledger--a value measurable and calculable, mind you--any less objectively real than "the distance light travels in 1⁄299,792,458 of a second in a vacuum?"
Because whether a human perceives it or not a ray of light travels that distance through a vacuum. The blockchain doesn't really exist without human perception it is not objectively real it doesnt exist without us, it is a concept of man.
Sure the blockchain exists.
Those markings in the Bitcoin ledger exist, just as much as ink markings made on a piece of paper. It's as real as a skyscraper, a bestselling novel or a computer virus. If every human on earth suddenly dropped dead, not only would the blockchain still exist, it would even continue to be updated for quite some time (until the power grid failed, anyway.)
Just because it's man-made doesn't mean it's "not objectively real."