Because you register this month and not before 22 August 2017. Check your image and you'll see.
What about people who registered at 22 August 2017 (not before or after)?
Airdrop rule 3: "All accounts registered on bitcointalk.org after August 22, 2017 are not qualified."
So people registered on August 22, 2017 should be qualified, right?
You should be accepted as the rule say "after August 22, 2017" . Try register and see what site say and take part of this airdrop.