Go doesn't have some of the most library functions, so large codebases shared between teams end up with a dozen different implementations of functions like "minimum" or "filter".
Yeah no offense but most of the people online that I find complaining about Go used it a long time ago or got their talking points pre-generics and haven't touched it or really looked at it since then.
Does https://pkg.go.dev/slices#DeleteFunc not work for you or do you need it to be called filter? It's there for maps too https://pkg.go.dev/maps#DeleteFunc