I see where you are coming from: you seem to base your argument on the assumption that there is no absolute moral truth. If so, good and evil only exist in one's mind. If you really believe that, then your logic dictates you must also support the anti-vaxer's choice.
I sense a contradiction in your logic. You seem to deny that it is a living organism but yet you admit that it can feel pain.
Your answer still dodges my argument that this pain-feeling fetus at that stage is still a living being, presenting a moral challenge for anyone who would take the life out of it. So, what does this mass of cells have to NOT exhibit for it to be ethical for one to do away with it without guilt? Heartbeat?
(So all a pregnant woman has to do is deny that it’s a baby and then it is no longer a baby? 2+2=5?)
It is not just me taking this position. I recommend the Mayo Clinic‘s description of embryo/fetal development. “It” has a nose at 8 weeks, toes and fingers at 9 weeks, and even sex organs at week 11 (gender). Almost from the beginning the DNA is set for this living creature, which sets it apart as having a unique identity.
In return, let me thank you for speaking for the millions of sets of vocal cords that never had the opportunity to utter a single word on their own behalf. Maybe they appreciate you assuring us that their “matter” never mattered.