Does Mythos mean you need to shut down your Open Source repositories?

In response to concerns about Anthropic's Claude Mythos AI model being a powerful hacking tool, the author argues that open source developers should not close their repositories. Key reasons: open source code has already been ingested by AI training pipelines, most vulnerabilities exist in dependencies and supply chains rather than custom code, and closed-source systems are equally vulnerable to analysis. The author cites the UK AI Safety Institute's evaluation of Claude Mythos and NCSC guidance, neither of which recommend closing open source projects.