I'd say that everybody has a natural right to not fear malicious harm while engaging in any form of everyday commerce or public discourse.
In situations like the hypotheticals described, I would also say that the local authorities have lost their mandate to govern, and that those subject to the adverse conditions are ethically justified in securing their own safety by any means at their disposal, including against those (former) local authorities, if necessary, while still engaging in everyday commerce and public discourse. Making everyone stay home to stay safe is not an acceptable option. Living your life is more than just avoiding an untimely death.
You do have the right to do business at a laundromat without the threat of being killed, but it is not the owner of the laundromat that has the ultimate duty to provide the illusion of physical security there. If a state exists, it is the state's duty to make you feel safe anywhere in public, provided that you do not yourself act unlawfully.
No government upholds that duty perfectly, however, so a certain measure of responsibility for one's personal safety will always fall upon the individual. And in order to safeguard the benefits of trade, a certain measure will always fall upon the business owner who wishes to keep their customers (and unpurchased property).
Facebook has chosen, perhaps wrongly, to implement its policies such that it is easier (and cheaper) to hold misbehaving individuals accountable after the fact than to protect innocents from misbehavior before it happens. This is a business decision, and it reveals by its failures that state authorities are not effectively investigating and prosecuting criminal harassment to the extent necessary to make people feel safe, and in the worst cases, it is the state authorities themselves that are harassing identifiable individuals.