From the Guardian today:
How do I tell someone they are not behaving safely?
Ask yourself first whether or not you are enjoying playing the world’s police officer a little bit too much. Delivery drivers and other essential workers report having been harassed in the street for being out, when they are on their way to work. It is much easier for some people to self-isolate than it is for others, and consider before you judge someone else’s behaviour the possibility that their situation is more complicated than you appreciate. There are very few circumstances in which upbraiding someone will be more effective for your safety than simply moving a bit further away from them.
There seem to be an awful lot of posters who are over-invested in how everyone else is behaving, without knowing anything of their circumstances. And who think that ranting to the 'offenders' will somehow make a difference. When it won't. It'll either upset them (because it turns out they're dealing with more than the preachers know of) or make them even more stubborn.