I've seen lot's of people who complain to bounty hunters who dump their tokens after they get them. Why hate them? They have all the rights to sell whenever they want and bounty allocations are only 1%-5% of the total supply of the coin. I don't think it will do much to lower the price of the coin. I mean it's even good for the ICO investors as they will have a chance to buy more tokens with lesser price than the ICO.
Holding the tokens also doesn't mean it will make you rich. Some tokens get abandon by the developers so it would be better to sell at a good price than be left hanging in the end.
In some cases, the dump created by bounty hunters can have domino effect.
The dump might be scare the investors who hold a big amount of coin, and can causing they to sell the coin in massive amount.
But bounty hunters is not to be blamed, because they just want to use the money they received from their works.