True, but it's sort of like divorcing your spouse because s/he keeps whistling through his/her teeth, rather than speaking up and saying, "You know, that really bothers me, and I would consider it a favour if you stopped doing that."
It's a bit extreme to say they're the same thing. When one marries, you enter into a partnership both legal and (in many cases) spiritual and you commit to each other. When I accept a friendship in Facebook, I don't commit to the person in any way. The Facebook friendship is not a re1ationship I feel is even close to the same level.
I have one friend who has a cat phobia. Cats freak her the heck out. I didn't find out until she declined multiple invitations to my house; she knows from my photos on Facebook that I have a cat. (Most of my pictures are of my cat. What can I say, she's adorable.) She felt bad because she thought that I might be taking her refusals the wrong way, so she let me know. My bet is that she has my photos unsubscribed, if she doesn't have me hidden altogether. I'm not offended.
She could have asked me to stop posting cat pictures. She could have asked me to exclude her from the list of people who see my cat photos. Neither is reasonable for me to do. I post almost all my picture from my phone and they just go automatically to my photos. I could block her from my photo albums, but she can do it herself just as easily if she wants to. I expect her to manage her phobia herself. As far as I know, she expects to as well.
I find it interesting that there are people who assume that if they are bothered by certain images, then they must be in the majority or part of "most people". Unless there are statistics out there to back it up (and I doubt I'd consider a poll of this post to be "evidence") I don't buy it.
If you think your FB friend is a bad person, unfriend them. If you just don't like the pictures they post, unsubscribe to their pictures. As someone said on another post, we cannot control how others behave, we can only control how we react to their behavior. Facebook provides you with many tools that enable you to see or not see various things. Feel free to use them.