For many years I've been an angry advocate for the dismemberment of those who misuse the phrase "beg the question." Why did I stand so firm on the side of grammatical purity? Because people were out there, people who were otherwise not to be considered evil, using the phrase improperly. But recently I've seen that my own justification itself begged the question. Misusing "beg the question" was wrong because it was wrong to misuse "beg the question." Such logic is textbook question begging! And this realization, in what I formerly considered to be incorrect usage, further begged the question: why did I even care?
It pretty much comes down to two things:
1) Pragmatism. People, institutions, publications, and authors whom I respect all utilize the phrase "beg the question" using the new, theoretically incorrect, meaning. It's a losing battle. For the most part, if you use the phrase properly (to point out circular logic) most people, even well educated and otherwise grammatically prudent people, don't know what you are talking about. They stare at you and wait for you to follow up with a question that was begged, a question that won't ever come. So as a "beg the question" purist I spent my time either a) berating people for using a phrase the way 99% of the rest of the population now uses it or b) sounding like an idiot.
2) Realism. (Okay, "realism" and "pragmatism" are synonyms, but I couldn't think of a good one-word heading for list-item number two.) The fact of the matter is people who are using the phrase "beg the question" with its new, altered meaning are actually making perfectly valid grammatical sense! Though the phrase "beg the question" is meant to point out circular logic, based on changes in the English language, specifically changes to the usage of "beg," the WORDS "beg the question" do, in fact, mean exactly what most people now use them to mean. Often purists such as myself state that people should say "demands the question" or "asks the question" instead of the incorrectly applied "begs the question." But though these alternatives would also work, that doesn't mean "begs the question" is incorrectly applied.
So, with that, I pass on the task of ridding the world of incorrect usages of "begs the question" to those who are more resilient against changing times and more duty-bound to archaic rules. I will not go so far as to start using the phrase with its new meaning, but I will at least stop correcting those who do.
Note: Actually, I'm pretty sure I'll still keep correcting everyone, but only because I enjoy being a pedantic know-it-all.

I think you're really toeing the line of grammar correctness.