This is exactly why Roe was probably the most masterfully created SCOTUS opinion.

The four year old they mentioned isn't a person in any meaningful sense because personhood is based on consciousness.

This isn't a new argument. John Locke, who the PATRIOTS might recognize from the line "life, liberty, and the pursuit of happiness" (Locke's original line was "life, liberty, and the pursuit of property") wrote that if a prince's consciousness was swapped with a cobbler's consciousness, the prince would exist in the cobbler, and the cobbler would exist in the prince. This is supposed to show that only consciousness (memory, psychological connectedness) dictates personhood.

Roe didn't take this vision of personhood. The SCOTUS, once again, was conservative. They entertained the flawed body theory of identity. They ruled that if the fetus was viable outside of the mother's womb, then it had rights, but only at the point of viability. They still championed potential life, but they recognized that a clump of fucking cells isn't going to be a person until much further (years) down the line.

This is also why their "you're okay with killing babies" bullshit is asinine. But fascists never argue in good faith.