Remember that the semantic range of the English word "apology" is significantly different than that of the Greek work απολογια, whence our English word is derived. Απολογια does not have the sense of "an expression of regret" or "the seeking of forgiveness," but rather "a strong defense." So an apologist is someone who defends a particular school of thought.
Classically, "apologetics" and "polemics" have been closely tied together, with apologetics being the defense of one's particular ideology, and polemics being an attack on contrary ideologies.