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.
Yeah i agree there is no rule that you can't sell your tokens at a particular time and that is what i like about crypto, nobody dictates us on what to do with our portfolio or tokens and it is up to us. Just trust your instinct and follow it because after all it is your token and not theirs.