The Locus Classicus for apologetics comes from 1 Pt. 3.15. My position is that anyone can be an apologist regardless of what is believed to be true by that person. There may be Christian, Muslim, Atheist, Darwinist, creationist, or agnostic apologists. The subject alone is broad and the predicate does not necessarily entail a religious belief. I’ll refer to our Locus Classicus for our understanding of an apologist/apologetics.
But in your hearts honor Christ the Lord as holy, always being prepared to make a defense to anyone who asks you for a reason for the hope that is in you; yet do it with gentleness and respect.
κύριον δὲ τὸν Χριστὸν ἁγιάσατε ἐν ταῖς καρδίαις ὑμῶν, ἕτοιμοι ἀεὶ πρὸς ἀπολογίαν παντὶ τῷ αἰτοῦντι ὑμᾶς λόγον περὶ τῆς ἐν ὑμῖν ἐλπίδος, ἀλλὰ μετὰ πραΰτητος καὶ φόβου,
πρὸς ἀπολογίαν (pros apologian), “to answer everyone.” This term is used of a formal defense in court against specific charges (cf. Acts 22.1; 25.16; 2 Tim. 4.16). In a more general sense ἀπολογία (apologia) refers to an argument made on one’s own behalf in the face of misunderstanding or criticism (1 Cor. 9.3-15; 2 Cor. 7.11). Perhaps closest in meaning to the present passage in Paul’s use of the term in Phil. 1.7, 16 where he views his own formal “defense” at his impending trial as an occasion for the “defense of the gospel” on a wider front. Here, the language of the courtroom is being applied to informal exchanges that can occur between Christian and non-Christian at any time (ἀεὶ) and varied circumstances.
The biblical use of the term is in the context of one defending one’s own personal belief. The legal connotation implies defending certain propositions one holds to be true. So, if I’m a Christian can I be a Muslim apologist? No. I think apologia constrains the use of the word to exclude playing “devil’s advocate.” I can certain argue a Muslim position on something, but merely because I argue for the truth of it in that moment does not make me a Muslim apologist. When we use the term Christian apologist, the subject (apologist) is very broad. When you introduce the predicate (Christian) then it delimits the scope of the subject’s [otherwise] general applicability.
A Christian can certainly take on the role of a Muslim apologist in a discussion but taking on a role of X is not being X. In other words, the predicate constrains the subject’s scope as it pertains to reality. Only a Christian can be a Christian apologist and only a Muslim can be a Muslim apologist. To interchange the understanding of the constraining predicate with a pseudo role would an illegitimate understanding. If we were to interchange the scope between the predicate and assume one taking on the role of that predicate would mean that if I propose any proposition that is a shared proposition, with true value, then I will be an apologist respective of any ideology that affirms that proposition. So if I say, “love others as you love yourself” then I would become an apologist for Christianity, Buddhism, and anyone/anything that affirms that proposition. It’s true to say that many propositions are shared amongst ideologies but that’s all I’m arguing for in the first place, all truth is God’s truth and I’m coming at that proposition and placing it in a Christian context.
To sum up my position, to be a Christian apologist you must be a Christian. You cannot be a Christian apologist and a Muslim apologist at the same time. This is different from merely arguing for the truth-value of propositions; it constrains this to a personal (respective of one’s self) defense/articulation given the biblical understanding.
 J. Ramsey Michaels, 1 Peter, WBC (Waco, TX: Word, 1988), 188.