Because it already implanted. The body has already done all the implanting it will for that conception. It would require a bizarre system override and reattachment to the uterine wall that just can't be done.
The uterus already believes the body is pregnant even though it was in the fallopian tube. The hormone profile has changed etc.. from when implantation could have occurred. (Biologically speaking).
It's like they think it can be plopped into the uterus to reattach when in fact fetal death will occur after it's been detached from the Mom (as she's the source of everything until birth).
Just like they thought aborted fetuses could be reimplanted....

@RavenCT Hmm. Although I still wonder at more of a transplant approach, of placenta and all. So could it be implanted into a surrogate's uterus? If so, could it be frozen until such time a surrogate is available? It's not that I'm advocating against aborting ectopic pregnancies, I'm just curious and it could point out a different path pro-birthers could take.

I think I generally have a problem with absolute proclamations by supposed experts, who think they know it all.

Then there's this: Tubal embryo successfully transferred in utero. [ncbi.nlm.nih.gov] Follow the LinkOut resource.

@bingst Well shit! That's one on me? I had no idea that could be possibly be done.

So now the question is - are there repercussions if the transplant doesn't take? I wouldn't want to be a woman capable of reproduction in Ohio at the moment.

Various groups I'm in on FB have women who are running to get IUDs implanted to prevent pregnancy in case of rape.

It's beyond extreme there. And it's all religiously motivated.

@bingst Actually after Googling every article on this subject is old. Like 1980s? I am wondering if they mistook a secondary pregnancy as reimplantation? You'd think this would have become common practice?

Though if an ectopic pregnancy is caught early enough they end it with methotrexate. It's just a drug intervention - no surgery...