I guess I gotta wave my "descriptive not prescriptive" flag a bit. =) You are, technically, correct. Hermes Conrad aside, technically correct is not the best kind of correct--"apologist" has nearly universally negative connotations in, well, modern English, here, now. It is used almost exclusively to characterize a position that the user of the word views as negative. And people who don't fall into that generality often are using the word in "defiance" of that generality, which kind of makes you wonder why, when words are used to communicate. It's also worth noting that at least some dictionaries characterize "apologist" as a defender of something controversial, which is a nod towards the real-world use of the term if you read into what they mean by controversial a bit.
The world isn't an SAT test. Context always always always matters. (And, for extra context-matters, if you are now compelled, at the end of this post, to ask what a "Standard Aptitude Test test" is, I invite you to take a good long look at your life and ask yourself why you want to be That Guy because nobody likes That Guy.)
Sure. But the use of "apologist" in a Christian context is, today in 2015, much more niche than, say, calling the news organ of a particular political stripe "liberal apologia"; it would be rare to see the New York Times use that phrase except in irony but much more common for conservative sources to do so, because it's commonly understood to be more negative than neutral.
It's much the same as getting mad when somebody uses "hacker" to mean something other than "train and/or computer nerd". You don't get to lay a prescriptive claim to truth.
I am an apologist for the ideas of democracy, the rule of law and equality before it. As I am for certain aspects of attempts to achieve such. I am not any kind of apologist for facism, totalitarianism and ideologies that lead to such.
From a slightly different angle that may make the example clearer:
The so called "2 party" democracy has it's drawbacks, one of which is often labeled "partisanship" or something like that. I am an apologist for that, while acknowledging its imperfections and problems. The concept of the loyal opposition is the thing that seems to have worked best so far, I would argue it has worked best by such a huge margin that alternatives are scarcely worth considering other than as the enemy of freedom.
Not if you know what the word "apologist" means (it has nothing to do with ridicule). Try using Google.
Edit: dang has criticised my last sentence there, which is fair enough. It was meant as a dig. However, if you are unsure of the meaning of a word and are using either Firefox or Chrome, you can select the word, right-click, and choose "Search with Google" and Google will actually give you the definition for that word. It's a (relatively) new feature they've added. Also, search with "etymology" to find the origin of a word.
You disagree with someone, awesome. That's not a reason to try to ridicule that person imo.