I'm really sorry, but you simply aren't getting it. If you operate with your family they way you are on this thread, then perhaps they find it difficult to manage interactions with you.
You cannot expect them to talk to you about your siblings, their life or their events - you are NC and that is your choice. Do not blame them for a choice that you have made.
You cannot expect them to not put up photo's of the weeding or the christening because you are NC. It is you, not them, that is NC. They are in contact, and it is their mantelpiece, so they can dispaly what they want, and you don't have a right to object or find it uncomfortable.
You can't expect them to apologise for the fact that you weren't invited - you were not invited because you are NC and it is neither up to them to explain that nor to apologies, because it isn't their wedding.
If you never see them, how are you spotting the photo's of weddings and christenings on their mantelpieces?
I really think you need some help about this. You are making everything about you. The wedding etc is not about you. It is about someone you have no interest in, and are NC with - so you have no right to comment or complain. But if this is how you are coming across to members of the family, it is you who is putting them in an impossible position, and I can see why they may find being with you uncomfortable. Perhaps some therapy to help you process why you act like this may help? Family dynsamics are always complicated, but they simply do not rotate around one person and their demands, and this is how you are coming across.