In both cases I don’t think the plug should be pulled. In the first case, someone already had a complex experience with memories and dreams and whatnot and you’re contributing to them never waking up. The existence at some point in the past still matters.

In the second case there’s no reason at all to do something so drastic. Abortion is acceptable only because the mother’s body is being used and damaged, and she should have the right to prevent that use. The preemie doesn’t need to damage someone’s body to exist.

Edit: having read some of your other comments, I have a question for you. Why should we care about a zygote and not a sperm and an egg. Why is the act of fertilization the line between simple reproductive cells and a beautiful human life. Both have the potential to make a person, both are genetically human, both likely cannot experience things in a human-like way.

Are you genuinely not already aware of the biological difference between a (haploid) gamete and a (diploid) organism? This is like 7th grade science stuff, so I want to understand if you're questioning whether there is a difference or whether the difference matters.

Zygote, embryo, fetus, infant, toddler, adolescent, and adult are all different stages of the life cycle of a human organism. Gametes are not. Before fertilization, there are gametes. Unless fertilization happens, no organism comes into being. But once it does, it is the same organism from then all the way until its death. This is a biological reality, not a philosophical one.