If the intention was to allow telnet login over the internet, they'd also have added hole punching so accessing the port doesn't require bypassing the firewall.

If the intention was to allow telnet login over the internet, they'd also have added hole punching so accessing the port doesn't require bypassing the firewall. The design is more consistent with a debug feature intended for troubleshooting by someone on the same LAN. Of course the debug interface shouldn't be so easy to access, but that's just stupidity, not malice.