“Why is anyone so intent on disproving the scientific statements of Chazal?”
I’m not. I’m objecting to people who insist on *proving* the scientific statements of Chazal when the halachah has been since the time of the Gaonim that we *don’t* follow their science.
“Could not Hashem have created a universe that was billions of years old?”
Of course the answer to this is yes, but that is a Christian idea with no basis in our mesorah. In our mesorah we find opinions that follow the apparent pshat which would be that the universe is thousands of years old (see Seder Olam Rabbah) and other opinions alluded to by others that say that the universe is much older. There is no psak for aggadata.
“in the gemara you will find math and science too “
Correct.
“perhaps it is not an halachic issue, so we should not be so concerned about it”
Correct.
“So if they misspoke about lice and its source, or if they understood it differently, big deal. They still knew what was treif and what was kosher. “
Correct again.