The primary reason is that a statically linked glibc can't use NSS (Name Service Switch) modules from a different glibc version, so if you statically link glibc

The primary reason is that a statically linked glibc can't use NSS (Name Service Switch) modules from a different glibc version, so if you statically link glibc you can't reliably resolve names with getaddrinfo. You can do DNS with other libraries, and many applications do anyway because they want asynchronous DNS and NSS uses static DNS, but you can't really do anything other than DNS or static hosts files. musl, on the other hand, never supports NSS, whether static or dynamic, and exclusively supports DNS. You can't resolve things like mDNS names, or even resolve localhost if on a system that doesn't hardcode it in /etc/hosts. So either way, static linking and name resolution don't mix well, and musl and non-DNS name resolution don't mix well.