I hope you can remove the 0.01 ETH fee if you really want to airdrop your coin. Asking for a fee on an airdrop will raise a lot of questions and people will doubt if the project is legit.
The airdrop is nit the only way to distribute STC. The fee is less then 2$ to prevent spamming.
Thats not a good reason, you cant give a better requirement for the airdrop to avoid spammers instead of asking for sending few bucks to your eth wallet. It is a fishy thing for an airdrop, of course it is not recommended for everyone to join the airdrop imho.