Unfortunately common things in one language often mean other things in another language. The author is clearly trying to share this with the English speaking world, (the site is English after all), so it stands to reason that you would choose your words carefully in English.
Interesting, so since it is/was used primarily in South Africa and Afrikaans has its roots in Dutch I'd guess that's actually the root of the derogatory use as well. As in "people traded with coin".
Probably unnecessary nitpick, but here goes: the actual derogatory term is "Munter" rather than just simply the word "Munt".
For example, I saw [INSERT NAME HERE] and they were looking like a total Munter. when it is used in a derogatory sense I think it is more often used when talking about [INSERT APPROPRIATE PRONOUN FOR PERSON WITH VAGINA HERE], but as far as I'm aware it can be applied to both/all/neither/X sexes/genders/species.
ETA: This is my second edit because apparently I don't understand how HN works after all this time. Mea culpa, mea maxima culpa.
No, the Oxford dictionary definition for the product's name as cited is correct in the regions it says it is. The existence of other, similar derogatory terms in other regions is secondary, if anything.
This is going to save me literally seconds over the course of my lifetime, and as one with absolutely no patience with how slow computers are this is the best thing I've learnt this week.
This is also coming across as a really sarcastic reply, but it's really, genuinely not and I am very grateful that you pointed this out. Again, see hugs above.
Interesting, I always equated pills with "munted" but those other permutations always meant something very different. Maybe it's a regional thing in the UK?
Wiktionary says that munter and munted are from New Zealand, which I'm not sure about but could give it a regional spread - it's been common here in London for nearly two decades, but we have quite a few Anzacs here!