No one said they did. The bacteria is already present. The mones do not create more bacteria but they will convert to stink when used in these areas because of the higher bacteria content which is natural even after you have showered.
For example tests show that one popular mone I believe its anol can convert to anone when exposed to higher bacteria levels. I think there is a study on it in the studies and abstract.
Bacteria and mones do not mix. Its just one of the things that distroys the signal you intend to send.