Here it just means they can't trace the source.I suspect that the after-action report will conclude the term "community spread" was techno-babble to avoid saying "the virus can transmit through the air".
Someone in the community has it who hasn't been overseas or had contact with travellers.
If it's airborne you would have a higher number of people. Sounds terrible but Covids very mild as Pandemics go. It's not that fatal not that contagious.
You don't need to yeah for the hills with your favorite selection of AR-15s. Don't be an idiot either.
It's not that hard to overwhelm the health care system though that's the problem.
Not that they can do much anyway they can save a few of the worst effected via Ventilators.