If it’s a job that requires high-performance/low-level code (which seems to be the case from the other qualifications), this is probably their way of filtering out people who have primarily worked at a higher level where you don’t need to worry about the nitty-gritty details
I can almost guarantee that job post was written by a recruiter who had some engineers in a call. The recruiter probably said something like “What about Java? I hear Java is important” to which the engineer(s) likely jokingly responded “Oh, no, please no. MINIMUM POSSIBLE JAVA. Yeesh. Ideally none.” … and the recruiter took that literally.