There’s really no mystery about mask-wearing sense. Mask wearing is not about you it’s about the population, so the question is:
Q – Is it selfish not to wear a mask?
A – It depends:
We should adopt (in fact were gradually adopting before the Covid pandemic in my experience) the Eastern SARS / respiratory infection mentality.
If you know you have a relevant infection, you should self-isolate for the benefit of others. The main downside to this is people whose income and job-security suffers from missing attendance at work, and that should be addressed directly.
If you must attend workplace and/or public transport / spaces when you know you are infected, you should (at least) wear a mask and “socially distance” so far as possible to (a) minimise infection of others and (b) signal to others that you are a risk, so they can socially-distance too.
If you don’t know you’re infected but suspect the risk of infection – eg you’re out at work or in public and detect that you’re maybe “coming down with” something, as you do, or you recognise a risky context – in crowded sweaty, poorly ventilated public transport or event with infection being notably prevalent in public – you should take steps to isolate and/or mask-up. Even visible improvised efforts have value in signalling to others at risk (*).
If your workplace involves vulnerable people or makes you more vulnerable, it doesn’t change these rules, just makes the risks and the rules more important to respect. Specific additional, detailed occupational rules may apply.
Everyone should avail themselves of public-health-provided vaccines unless they have good reasons of personal risk – including minors if practical & available. We shouldn’t be obsessed with exactly who has or hasn’t been vaccinated provided high adult population numbers are achieved. Minors – schoolkids – are not generally vulnerable to illness from SARS infections.
And note, wearing a mask is not about you it’s about others. Even if you think you’re wearing it to reduce catching the infection yourself, you’re doing so in order to avoid the spread.
Travelling between different public-health jurisdictions is a separate matter. The suspected risk end of the above common sense should apply until such time as both jurisdictions have agreed the same steady-state context.
The default should not be to wear a mask outside such risk-based contexts. The human face is a large part of social communication, and our freedoms are restricted physically and psychologically by the wearing. No surprise that idiot activists choose masks and hoods to disguise (or is that signal) their true anti-social-establishment motives.
Other things like hand-washing between contexts or capturing sneezes and coughs, even in a non-infectious context, are just basic good manners.
How hard can it be to be “sensible”?
[Aside: I am constantly amazed how moronic Jeremy Vine is – whether it’s Eggheads or his Radio 2 show, but I sometimes I listen in hope of detecting it’s some kind of double-bluff journalistic “act”: something like: – when it comes to asking questions, there’s no such thing as a dumb question – but man! his inane comments just give him away. As public morons go, he is a fascinating case study.]
[(*) More constructive Post Note: One feature of respiratory infections in modern life – colds, flu, pneumonias (viral and bacterial), SARS & Covids – is that whatever the specifics of each, which symptoms, how severe the feelings of illness, the trajectory of the infection, the best initial treatment is rest (physical and mental) and suppression of the symptoms (eg by analgesics). Stressing the body and mind by soldiering on is the killer. Elite athletes know this, some of them collapse and die, even if the illness is from a controlled dose, like a vaccine. Mask-wearing has two-way symbology when you have, or simply see the risk you might have, such an infection. A warning and an admission. “OK, when I get home, I’m going to take an aspirin and lie down in a darkened room, you should think about it too.”]