I'm amused by that link, but I disagree with the underlying premise.
The English language has reason and rules and rhythm, and when it is used fully and intentionally its beauty can bring me to tears. Yes, proper English is at risk as fewer people each year are learning to use it well. And, perhaps devilishly, I'm now firmly in favor of striking the word "like" from our lexicon completely... there are workarounds.
However, language is a medium, not an end in itself. It is a tool for the exchange of ideas. If modern presidents want their ideas to be understood (and therefore accepted) by the general public - something that wasn't necessary before the advent of television - tailoring their message to the public's level of education is necessary.
Suggesting that governing language should be aimed at the well-educated is deliberately exclusionary. Most people aren't. Using language as a weapon against those whom it was designed to serve is undemocratic. Furthermore, deliberately ridiculing those whose only crime is their embrace of the speech patterns of their own time is at best elitist and pretentious. At worst, it is a sign that higher education has failed. The transformation of an open, seeking mind into a closed and bigoted one is a tragedy. And bigotry is a far worse malady than ignorance. The latter can be cured by education and opportunity; the former is a disease of the spirit.
To the extent that any speaker is understood by his listener, he has used language well irrespective of his word choice. There are people who are unwilling to accept that truth. In a fast-paced society where information is the primary currency, they risk being left behind.