Then the problem is with mixing the editorial history of the Avengers and the in-universe history of the Avengers. From an editorial point of view, ALL those teams are Avengers-related (even the Thunderbolts: there were former Avengers villains, had frequent crossovers with the Avengers, Hawkeye moved from one team to the other, and were both managed by the same writer when they started). From an in-universe perspective... perhaps the teams before Wanda's attack other than WCA are not officially recognized, but same goes for other teams after it. The Young Avengers just stole the name, Dark Avengers are all villains and surely nobody acknowledges Norman Osbourne or Bullseye as Avengers, and Savage Avengers were more of a "let's get together for this fight" team-up than a regular team. Even when published in comics that explicitly had "Avengers" in the name.