Just because a lot of people agree on something based on shallow observations does not make it objective science. Thats moreso the realm of subjective "soft sciences" like sociology.
What if the people entering the cave make non-shallow observations and report it back to you?
If that's still not enough, then sadly science is not enough either since it relies heavily on cooperation (you can't test everything yourself).
And how does genetic testing objectively tell you that it’s a lion? Genetic testing tells you that its DNA is similar to something else you’ve previously identified as a lion, but if there’s no way to be sure if that identification then you’re just moving the problem.
Just like radio astrology is far more scientifically revealing than just looking up at the night sky and declaring theres nothing more to the universe than meets the eye.
Typically a genetic variance of >2% indicates a different species