I'm not a doctor, nor do I play one on TV, but in my opinion what you are doing is directing your frustration/anger (a natural step in the grieving process) at your niece right now.

Also, disrespect is relative. My mother in law died a couple of years ago. She had always been very clear with her final wishes. Cremated, absolutely no showing, memorial service at the town hall, burial at the local cemetary.

Upon her death, we all got together to make the arrangements. There were five children, my husband being right in the middle. He and I had been together 25 years at that point, his younger brother (next in birth order) and his wife had been together for 20 years. The oldest child's husband of a whopping year was the loudest during the plans. He didn't even know the woman!

He decided she would have an open casket funeral, in a church etc etc etc. We won the battle of the open casket as even the quiet second child refused to go to the funeral until after the casket was closed as her mother made her distaste for this clearly known. It was a beautiful service, however I felt it was extremely disrespectful to defy her last wishes by having the ceremony in the church, given by a priest she held in utter contempt.