In a Sybil attack, the attacker subverts the reputation system of a network service by creating a large number of pseudonymous identities and uses them to gain a disproportionately large influence. It is named after the subject of the book Sybil, a case study of a woman diagnosed with dissociative identity disorder.

Are you claiming the 20 witnesses pushed into consensus by a single individual were not "pseudonymous identities" but known, trusted members of the community voluntarily put into a position of leadership by the community according to the intended design of DPoS?

STEEM, clearly, is not Sybil resistant enough. This was a Sybil attack. Pretending otherwise is not defensible. If noganoo had enough stake (or enough influence to get exchanges to do what they did), he could attack the chain through this Sybil strategy just the same.