It's the way it's processed - African beekeepers are always told to use loads of smoke and some beekeepers really do lay gouts of it on so that will get transmitted to both the wax and the honey. The wax is also rendered down on open fires, often using green wood (I may have some photos somewhere of them doing it) so that will lay even more smoke down.
I have found if the beekeepers are using 'modern' top bar hives and using them responsibly then most of the wax will be seldom brooded and nice and clean - here's some wax from the Selous/nyasa wildlife corridor in Tanzania
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But if the beekeepers are using traditional log or bark hives then the whole colony is killed or driven out (again using loads of smoke) and they will render down everything including any old manky brood comb they find.