That's because on Linux systems it's typical for domain name resolution to be provided by glibc. As a result, people ended up depending on glibc. They were writing GNU/Linux software, not Linux software.

https://wiki.archlinux.org/title/Domain_name_resolution

https://en.wikipedia.org/wiki/Name_Service_Switch

https://man.archlinux.org/man/getaddrinfo.3

This is user space stuff. You can trash all of this and roll your own mechanism to resolve the names however you want. Go probably did so. Linux will not complain in any way whatsoever.

Linux is the only kernel that lets you do this. Other kernels will break your software if you bypass their system libraries.