In part, presumably, because Ebola appearing in Atlanta would be extraordinarily unusual. East Asia has a history of novel respiratory diseases, the same way that other parts of the world have a history of mosquito-borne blood diseases.
Put another way: everything we know so far is circumstantial, and some pieces of circumstantial evidence are (or would be) stronger than others. An Ebola outbreak next to a BSL 4 lab in the United States would be a significantly stronger piece of circumstantial evidence than a coronavirus outbreak in a transportation hub city in East Asia.
So lets change the example sense you will fixate on Ebola as being rare. Bird flu was a big thing people were freaking out about a few years ago and it even made a real appearance in Georgia.
I stand by what I said if a new bird flu variant showed up in Atlanta, the media would be showing alot more skepticism and be looking at a lab leak far more seriously by the CDC just based on the geography. If we found out a few CDC workers had bird flu symptoms before the outbreak started, that the government started destroying evidence and blocking investigations, and a few researchers just "vanished", we would be looking at bare minimum a cultural understanding that there was a Jeffrey Epstein level of corruption and conspiracy in front of us.
Lets rewrite what you wrote.
"An Coronavirus outbreak next to a BSL 4 lab in China would be a significantly stronger piece of circumstantial evidence than a bird flu outbreak in a transportation hub city in the Southeast United States".
Unfortunately at this point its become political, the "its a lab leak" is a point that favors conservatives/Republicans/Trump, so a large amount of the population would refuse to believe it no matter what at this point even if proof was uncovered, and at best are heavily biased to disbelieve it.