Believing that this sentence is unduly harsh and acknowledging that it has occurred (along with the crime) in a context of a war on women (and the closure of half the abortion clinics in Ohio) is not the same as putting someone on a pedestal. It is possible to be horrified by the crime and want the woman's behaviour to be addressed appropriately (whether that means prison or another approach) and be able to see that this particular sentence is out of kilter with how men are treated for violent crimes committed within a very different context.
"She started trying to harm her baby long before she gave birth " This phraseology is buying into the women as vessels discourse. I am assuming that she wasn't consciously trying to "harm her baby" but that she was carrying on with life as normal. None of us know whether this is because she was in denial, or was intending to have an abortion which for some reason didn't happen, or what. But to phrase it as her consciously harming her baby while pregnant, is an extremist viewpoint IMO.
"The woman in question had access to the above."
We do not know this. You have to have money, support etc. to have real, genuine access to abortion rather than theoretical access. You also have to have a psychological ability to make the choice to terminate a pregnancy. Again, we don't know anything about this woman's psychological outlook, but it may be that abortion wasn't something she could confront. Who knows, it's all speculation. Apologies for getting it wrong on the age 21 thing, I read that somewhere and it's obviously wrong.
It is of course possible that she is just an evil psychopathic person with no conscience who deliberately decided to not bother having an abortion so that she could have the fun of murdering a baby. It's possible, of course, there are people like that, but they are extremely rare and it's more likely that she isn't. It seems inexplicable that she chose the course of action that she did, but we can either decide that we'll settle for inexplicability or we can decide to try and explain it, so that as a society we can choose to avoid creating the mixture of circumstances which led to her bizarre choices in the first place. We can't do that if we dismiss all attempts to try and understand, as "making excuses" for such behaviour.