I don't know whether rm is memory-safe or not, but vpr is. By 'memory-safe alternative' I meant that this alternative is memory-safe, but not that rm isn't.
Presumably other *BSDs use something similar? Didn't check out FreeBSD or anything.
Edit: So I suppose if you are using a BSD-type system (maybe including macOS?), and memory safety was important to you (to the point of extreme paranoia), then you might want to look into this rust project. Or just use the GNU implementation.