Gotta be careful here.

My understanding is that they conclude that because they locked down early and tightly it reduced the effectiveness of asymptomatic spread over time The paper supports lockdowns and congratulates wuhan on managing it well.

It doesn't really conclude "asymptomatic cases don't exist/aren't infectious" it concludes "if you lock people up over time the viral load reduces from person to person thus making asymptomatic people less infectious over time."

It also exptessely says you should lock things down, social distance, wear masks, etc.

I mean you're right in that they say that no people with close contact to asymptomatic people tested positive... But you also have to look at the conditions of those asymptomatic people. It's not like Wuhan had people walking around and living a normal life. They shut the whole fucking place down and used military style population control.

I guess that might be effective but not sure that's what we want to see...