Airdrops don't necessarily equal scam.  Airdrops can be a suitable method for distribution of a new coin as oppose to the ICO route.  Additionally, look at the coin and it's development.  Is there a viable product? Is there movement? Is there developer communication? This are the questions that determine if something is a scam, more so then airdrops/coin allocation.  


Additionally, how is an propositional airdrop in relation to the amount of coins owned be a scam.  Early investor and large investors take significant risk to help up a new coin, propositional distribution is the fairest model for airdrops.  If you want more, buy more.

Additionally, I see a number of post calling it a Ponzi scheme, if that is the case aren't all coins a ponzi scheme.  Early adapters earn the greatest returns.

Consider the facts before labeling anything a scam, just because it offends your sense of fairness, as oppose to the reality of the situation.