Terminology is extremely important, the words we use have meaning.

"Pro-abortion" implies (especially when compared to "pro-life") that abortion is to be promoted above other options or abortion is something good or something to strive for. The correct term is "pro-choice" because its not about promoting abortion, its about promoting an individual's choice of how to handle a pregnancy and making every option safely and readily available to them.

"Pro-choice" and "pro-abortion" are not synonyms of each other and calling the pro-choice movement "pro-abortion" is not correct.