In the context of language-arts education, a certain prescriptivism is unavoidable. There is a written standard, like it or not, and there are social consequences to violating the standard in certain contexts.
Karl Hagen's blog
Mark Liberman at Language Log has been at pains to point out how Bush, because of the stereotype that he is a mediocre intelligence and perhaps suffers some cognitive impairment from all those years of hard partying before he got sober, gets a bad rap for things that escape attention when they come out of the mouths of other people in public life.
That problem is hardly limited to journalists. English teachers frequently have the same problem. In this issue of Purdue OWL News [mistakenly dated 2007], an e-journal that answers writing questions, one of the OWL Tutors analyzes "is using" as a passive construction.
In the follow-up issue for the next week, the OWL news editor published a correction, but his explanation still leaves a lot to be desired.