That picture showed two families coming together. Everyone's eyes were on the baby who has united people from very different backgrounds. Also MM probably insisted on her mum being there because she wants her to be fully included and I think good on her. I also think Doria looks like a serene and classy lady who will be a lovely granny.
On a personal level, it reminded me of my MIL trying to shove my mum out the way when I had my first dc. My dh, who usually defers to her, sorted her out.
Stop projecting. They're not your relatives.
And let the baby be a baby, at least four a while. He's not an emblem of anything.