She wasn't a top-tier character, but she was a major character to anyone who read the Avengers books. She was one of the characters who had been in the most Avengers issues as a member of the team, up there with Wasp, Vision and a very few others. So she was a major character in Avengers in the same sense that Jean or Nightcrawler are major characters in X-Men; they're not stars like Wolverine, but they're major components of the team.
We've been through this argument many times before though. The story and the panels you posted are exactly the same, no difference, no matter who's responsible for wiping out mutants. But "blaming" a character for the fallout in books they didn't appear in, from an action that was not in character and has been retconned to be not really her fault, seems pointless. In other words what's important to the story is that the mutants were wiped out, not who did it. If who did it was important, the so-called villain would actually appear in those stories.