Yes, you can easily turn this into an autonomy question. But you're missing the point I'm making. Suppose you instead asked how pacifists can be in favor of laws restricting assault and battery, as this is like waging war against batterers.
I'd rightly point out that pacifists don't tend to like people getting hurt, and battery hurts people. You could turn this into a bodily autonomy question and point out that we violate autonomy with seatbelts so why not violate the autonomy of the punched, but that would be missing my point. Pacifists aren't all about bodily autonomy, they're concerned about not hurting people.
Similarly, I'm saying here that vegans should be against forced continuation of pregnancy, regardless of who's doing the forcing or who has control of your bodily autonomy. Vegans are against egg farming regardless of who the farmer is. Who gets to make decisions about the chicken is a different question than whether this particular decision should be allowed.
Note that I'm not making an argument for or against abortion. I'm only pointing out that being pro-choice seems to be more in line with vegan ethics than being anti-choice. I don't think vegan ethics are based on bodily autonomy arguments, so it's weird you that you keep bringing it up. Vegans aren't primarily concerned about bodily autonomy. Their concern is about not hurting animals. Humans are animals too, so vegans shouldn't want women to be hurt regardless of how the government works.
