You were banned, as the reason says, for participating in an on-forum altcoin giveaway. Specifically, you've posted to a now trashed ANN thread in exchange for future coins. Whether the airdrop started or not doesn't matter - you've participated by posting on the ANN thread and then claiming your spot to receive the coins. There are numerous warnings plastered all across the altcoin sections (in the form of stickied threads) that both starting and participating in on-forum altcoin giveaways that incentivize posting to one more more threads (either directly or through low effort tasks) is prohibited.
As for scammers, see
https://bitcointalk.org/index.php?topic=703657.0:
Q: Why haven't you banned who is an obvious scammer?
A: Possible (or real, not for me to decide) scams are not moderated to prevent moderator abuse. If we start picking out which ones we call "scammers" and ban, we would make a lot of decisions based on biased opinions.