> a quick overpass search finds lots of other similarly named shops tagged as "shop=charity" nearby

I am not fan of NSI style blind replacements based on name match and I am not planning to do them

> this kind of basic error

What exactly is basic error here? If I would spot the same kind of data nearby me while editing I would do the same kind of edit manually (shop=retail to shop=yes)

Do you mean being unaware that it is shop=charity?