Abortion isn’t their sole issue. It’s their moral escape hatch when confronted about their horrible political views. Their true motivation is racism, bigotry, and other deplorable views. It’s why the anti-abortion crowd keeps finding the worst racist pieces of shit in society to put into office despite having the numbers to determine the outcome of any republican primary. But when they’re confronted about voting for a horrible person, rather than giving an honest answer they can fallback on abortion. It also allows them to believe they have the moral high ground, because without the abortion issue they’d have to confront the reality that the rest of their views are awful.