Most of them have been trained to believe a bunch of malarkey by the leaders of the “pro-life movement”
Look at the great rivalries in sports: Yankees vs. Red Sox, Cowboys vs. Redskins, Celtics vs. Lakers, Alabama vs. Auburn, etc. These rivalries are immensely beneficial to BOTH teams, so much so that they have actually become interdependent alliances with the implicit understanding that ending the rivalry would be detrimental to both.
Politics is the same. Republicans and Democrats need the threat of the other to secure contributions and the power that goes with it, even though their agendas are nearly identical (and the ultimate sources of nearly all of their contribution is identical as well). BOTH parties are strategically aligned to insure that no third party can emerge to threaten them. Any prominent politician with a particular bent (socialist, conservative, libertarian, etc.) will be coddled and rewarded for putting party loyalty above principles.
And so it is with abortion at the upper levels. The leadership of groups like the National Right to Life NEEDS the American Holocaust to continue or their donations will dry up. The abortionists NEED pro-life opposition or their funding will dry up.
The whole thing has become about the issue rather than the outcome. The abolitionists wanted to completely abolish slavery by any means necessary including force, they wanted to accomplish this as soon as possible and then go back to their lives. In World War II the Allies wanted to force the Axis into unconditional surrender and then they wanted to go home. Yet all we see from Pro-Life, Inc. is ongoing fundraising to promote their latest "and then you can kill the baby" campaign.