I belive that is called a bonus, since airdrop doesnt require a purchese, when will you guys learn.
+1
These kind of things actually turn people away, just be open about what you're offering.
But they are open. They explicitly say "for every contributor".
And airdrop does not necessarily mean always free for everyone. Every airdrop I was in had some kind of restrictions (conditions if you will). This one has that you must own their token. I do remember I read some articles on airdrops a while ago where they mentioned that some projects might "change" the notion of airdrop and start airdropping for users who already own it. This must be one of them.
Just to be honest, I have bought some during pre-sale with a bonus already and now I get 10% on top of that? I'll take it anytime and be thankful for that.