You can't exactly put a country in jail so the only real way to punish a country is economically. Once we start talking economics, it is a lot easier to punish Bill Gates than a homeless man. China is #2 in the world in GDP and Laos is #118.
Beyond that, it wouldn't even make sense to punish Laos if the virus did have zoological origins there. The first outbreak didn't occur in Laos so there is little validity to accusations of a coverup or mishandling of that non-existent outbreak. The only reasons people have wanted to punish China is because they believe that China either created this virus and let it leak or that their initial reaction to the virus is what allowed it to spread globally. There would be fault in the case of China. There would be no fault in the case of Laos.