No! You didn't just compare a blastocyst to an ordinary one cell bacteria! You are lucky when you were in your blastocyst stage trying to attach to your host (your mother) - your mother didn't treat you like an ordinary bacteria!
By the way, there are good (beneficial) bacteria as well. They are called Probiotics. We need them to survive! It fights the bad bacteria and restore the balance within the body. Good ones keep us healthy by supporting our immune function. Certain type of good bacteria also helps break down food and thus help our body digest. It does many other things.
You won't survive without them.
Anyhow, the reason I mentioned blastocyst and after "plantation" stage - is because at this stage the embryo clearly shows signs of survival instinct. It shows signs of resistance from any possible rejection from the host. It not only creates an environment for its own survival - it even triggers hormonal changes in the mother to prepare the endometrium to receive and envelop the blastocyst. Many things works simultaneously to help the blastocyst to embed into the uterine wall.
Of course, one can argue life begins at fertilization with the Embryo's conception. However,
I believe - it becomes a mother's job to facilitate when the blastocyst attaches itself to the uterine wall. To do anything to detach it from there should be considered a violation. Most of us (human) won't even break a bird's nest with eggs in it. Even if a bird build a nest in a wrong place - most of us would wait until the eggs are hatched and the babies are safely moved. So, why no remorse in the case of a human?
Why support this?
Blastocyst (multi cell) is a later stage than Zygote (single cell). Even a zygote contains all of the genetic information (DNA) needed to become a baby. The fusion of the sperm (with 23 chromosomes) and the oocyte (with 23 chromosomes) at fertilization results in a live human being, a single-cell human zygote, with 46 chromosomes and that has all the characteristics of an individual member of the human species. At Zygote stage it is already determined if its going to be a boy or a girl!
I believe the life of the fetus should be protected from the moment of conception. The unborn should be considered as born from the moment it shows sign of self preservation. By creating an environment to attach to the uterine wall and by attaching and growing - an embryo shows more signs of survival instinct than even grown humans. Giving it the privilege is the right thing to do. IMO