Sorry you're dealing with this. FB is such a double sided thing. IRT someoen suggesting you "should" do something. I've said more than once to people who make such comments to me "Please do not "should" me. Thank you." And leave it at that. As for their offense, it is their choice. And, yes it is a choice to be offended.
It isn't like you posted something from an alternative minded source. It is a mainstream organization.