I do see your point, and I agree that the situation really is not fair to the people who get caught up in it with no choice in the matter. And if it were just her, I'd say she has every right to just turn around and walk away.
But because there are kids in the picture - which she did choose to have, for better or worse, not knowing what the future might bring - she owes it to them to do the research and make an informed choice, rather than a choice based solely on fear and assumptions. It's sort of like, if she were diagnosed with early-onset Alzheimer's, let's say. She would owe it to them to find out what her prognosis actually was, what the treatments were, how long she would be able to keep her cognitive functions, and to what degree they would likely become impaired before making the decision to ship the kids off to live with Grandma. It might not make a difference in her final decision, but at least her kids will know that she made every effort to make the right one.
Also, they are Lori's kids, too. (One biologically, the other two emotionally.) Once you've decided to have kids with someone, the two of you are linked for life. It isn't fair to the kids to declare that they will never see their dad again when there are other choices. Both of them owe it to the kids to do anything in their power to make this the least traumatic event possible for them. And that, again, means making informed decisions.
Now, one could argue that the most fair thing for the kids is for Lori (or any TS parent) not to transition. But in my opinion, having a miserable parent isn't any better for kids than having a TS parent. It's the same as when parents get divorced. Divorce is tough on kids, but so is living in a household where their parents constantly argue, or can't stand the sight of one another, or where one abuses the other.
I gather from your other posts that at one time you made the decision to walk away. And maybe the situation in your life dictated that that was the best course of action for everyone involved. I don't know you or your family or what the circumstances were, so I would never criticize you for that choice. We can't control other people, and sometimes it's better to walk away than to pull the children in two.
But I do believe that when both parents can approach any difficult experience with an open mind, and can work together civilly, if not amicably, then that puts a lot less stress on the children, and can only be better for them in the long run.