Precisely.. Telnet is Not an Application which is used to Carry out a DDoS Attack.. Its Merely a "Window" into another Remote System..
i.e You Can Access the System's Console / even GUI with Telnet.. More like Windows XP's Remote Access..
If you Have a Broadband Router.. Try to Telnet the Gateway..
i.e " telnet 192.168.1.1 " ,You Can Access the Router's Operating System (Which is Probably Stripped Down Linux)