> Is this how "MCP" server is typically implemented (no encryption).

No idea. The boring (in a positive sense) answer I'd expect for any backend API server is that encryption in transit is handled by TLS. So I'd expect either the MCP server in question can be configured to support TLS connections & refuse plaintext HTTP connections, or that for a production-like deployment it expects to be deployed behind a reverse proxy that is responsible for terminating TLS.