I'd be curious to know who they are, because their credentials should be in doubt.
Regardless of the effect of masks on COVID, there are some individuals who should wear them for a variety of indications. If they wear the right kind of mask and wear it properly, it can help them. They did it before the pandemic and will continue to do so after the pandemic is over.
So simply observing that somebody was wearing a mask and making assumptions that there was no legitimate reason is simply bad public health. That's not just being wrong about COVID-19 and it's not just a lack of empathy for person who was herself unsure of the details and just doing her best. That's just wrong on the epidemiology.