The reason the bounty hunters are seen as such is because once they already have their rewards they will sell their tokens right of the bat, but if you dig deeper in the market situation of the token you will see that it is not the hunters that are the reason of the dump. As one could investigate there are many reasons of a dump, the main reason will be the investors selling their tokens, another could be that the token have a market volume if that is the case then any small token sale will pull its price down so hard.