Disabling the service is a way to protect you from the vulnerability, but it is not a fix for the vulnerability. A fix for the vulnerability would allow you to continue using the service.
Maybe there are still old devices that don't support SSH and you literally have no option, but really, what other reason is there to have telnet enabled?
So, basically I think Ars Technica's sub-par quality strikes again, in that a tech site gets a fundamental understanding of technology wrong. If something isn't mission critical, can be turned off, and alleviates a vulnerability, then that's a way to fix it. Plain fucking English.