A request body in a GET is not standard HTTP. Refusing to handle non-standard requests might be inconvenient, but it's an eminently defensible choice.

I understand why you'd want it, and that's why RFC10008 introduces QUERY as a GET-with-body alternative.

QUERY, added in 2026, does not resolve existing or legacy applications.

Sticking to RFC is one thing. Advertising as node compatible is completely different altogether. Many people cannot see the difference.

Atleast a flag would suffice as that would ensure existing infrastructure tooling doesn't break while keeping the RFC spec folks happy.

Technically every http method can have a body? But the specification says the semantics are undefined on get and any compliant implementation is free to ignore it.