"So-called" RNA polymerase II???

The journal Cell has issued a press release announcing a paper from Roger Kornberg's lab in their Dec. 1st issue. [Nobel Laureate Finds “Elegant” Explanation for DNA Transcribing Enzyme’s High Fidelity, see Biology News Net for permanent link]

Last month, Roger Kornberg of Stanford University won the Nobel Prize in Chemistry for his efforts to unravel the molecular basis of eukaryotic transcription, in which enzymes give “voice” to DNA by copying it into the RNA molecules that serve as templates for protein in organisms from yeast to humans. Now, Kornberg and his colleagues report in the December 1, 2006 issue of the journal Cell, published by Cell Press, new structures that reveal another critical piece of the puzzle: how the so-called polymerase II enzyme [my emphasis] discriminates among potential RNA building blocks to ensure the characteristic accuracy of the process.

It's an interesting paper. That's not what I want to talk about.

I'm curious about Cell's use of the phrase "so-called polymerase II." This seems very strange to me. When I use the term "so-called" I intend to call into question the meaning of the words that follow. For example, if I refer to Bill Dembski as a "so-called" intellectual, it means I don't think he's an intellectual.

Are Americans in the process of changing the meaning of "so-called" in the same way that they're changing the meaning of "begs the question?" If so, it indicates an interesting trend toward strict literalism and away from more subtle meanings.

Should I avoid using "so-called" because Americans won't get the sarcasm?