There is no moral imperative to care about a parasite with no brain.
Well, since unborn babies have brains they are safe, right?
And since they are human, they are not parasites. We surely wouldn't label a fellow human - a parasite.
It is a parasite if its bearer does not wish it to remain within her body.
The rights of the actual living person carrying the fetus inside her body override the rights of a clump of cells that has the potential to become a person some day. You do not have the right to force a person to donate a lung or kidney to another person, no matter how dire the need. Why do you assume that this right should be taken away from a woman when she becomes pregnant?