In general, no, I do not agree. Not everyone who receives an airdrop is going to dump it immediately (personally, I don't do it). A good project will not be ruined by it. Yes, there are some projects that disappear shortly afterwards, but I think they were designed to do so. Moreover, a short decline in price after airdrop or ICO may be a good thing for investors who believe in the project: they can get more tokens or coins cheaply. Remember, when someone is dumping, someone else is buying these.