The recommendation from the CDC is that you only wear it if you're sick, so that doesn't seem to be missing at all. I haven't seen any official source recommend not wearing a mask when sick. The main problem is yeah: people can't necessarily tell if they're sick with COVID because they may be asymptomatic. But recommending everyone wear masks all the time just in case they're sick doesn't seem to be practical with the current supply.

If you're splitting hairs here about recommendations, it should be pointed out that being asymptomatic means you are not sick with COVID-19 -- which is the disease caused by the SARS-CoV-2 virus. One can be a carrier of the virus without being sick; and even those who are regarded as "recovered" can still contagious.

Thus, yes, the recommendation from the CDC is about those who present symptoms; it's not about those who are asymptomatic and yet may be infectious with the coronavirus.