Putting a justice on the Supreme Court is different from banning abortion. "If you defeat your enemies, they win" suggests that banning abortion will somehow "defeat" the Democrats and afterward they won't have political power anymore. That isn't the case; it would massively boost their supporters and give them an issue to motivate turnout, just like how Proposition 8 was the last gasp of Republicans in California that galvanized the gay political machine to crush them.
If people are like "uh oh, now I can't have casual sex without risking parenthood," it'll light a fire under them to change the law and vote out the people responsible for banning abortion. All the woke idiocy they preach, the tranny bathroom laws and CRT and homeless aid doesn't have that kind of power to move people because it doesn't directly affect their lives and choices. People support it because it reinforces their "enlightened" self-image but far fewer will actually volunteer and sacrifice time and money for it. If abortion is banned you'll see people volunteer for the Democrats who were never involved in political organizing before, people who aren't just doing it to fill a space on their resume so they can move up to more important political work.
And why am I supposed to care about unborn babies anyway? If Person A can't survive but for Person B, Person B is still within their rights to disassociate from them, the same as I wouldn't dispute the right of the Chandlers to evict Chris like they should have done. "Compassion for the voiceless and the less fortunate" is the reason the left gives for wanting to send tax money to increase birthrates in the third world and allow enemy invaders across our borders. Unwanted children go to the jails, the street corners and the tent cities and shore up the ranks of Democrat voters.