Quite frankly, that seems like the common attitude for most people these days. While I think we all need to be kind to one another in whatever way we can, I don't think you need to be a doormat. If you know that it's going to cause an issue for you to speak up then don't, and as for removing her from Facebook, can you just ignore her comments and not read them? Or just go off of Facebook altogether--believe it or not life does continue without social media. Actually it leaves you with a lot more time in your day to be productive.
What I really want to say, however, is this: You are not responsible for how people respond to your choices. If you are being respectful rather than purposely mean and hurtful, but are saying/doing something that needs to be said/done then you have done nothing wrong. Their response is their problem, not yours.
I come from an extremely dysfunctional family, including a mother who is mentally ill. I want to respect her and honor her, and I've had to learn what that means. It means honoring her choices. If she chooses to act crazy, that is her choice--I don't judge her for it or put her down for it. However, I also do not allow her to visit my home as it would not be good for my young children. It's not easy for me to have to keep her away from her own grandchildren, but she is making her choice, and I am making mine. I still call her every week to check on her, and we have long and pleasant conversations. I love her. But I will not sacrifice the health of myself or my family so that she can "feel better".
In the same way, I do not take responsibility for the emotions of other people. If I have done what I needed to do, in a way that is kind and thoughtful of others, it is not my fault if my choices upset them. Does that make sense? I am responsible for me. They are responsible for themselves. I'm responsible for my emotions and responses to the people around me (for letting them get under my skin, or make me angry, etc.) and they are responsible for their emotions and responses to the things I do.
Do what you need to do to be healthy, and don't be afraid to do the hard thing if it's necessary. Life is too short to spend it upset and stressed out over something petty.