Because other people do, and those people previously would have CLAUDE.md files in their repos and not AGENTS.md files. When you have to work with them and their repos, you were forced to deal with the difference.
Yes, but you see this is all part of Anthropic's master plan. They know developers are incapable of renaming files so the fact that Anthropic resisted Agents.md is proof that they were trying to lock you into them as a vendor.
