Not everyone sees things the same way as you. I don't believe in either funeral or memorials of any kind. (As far as I'm concerned the dead should simply be forgotten).
The only time I've visited my parents graves was to remove the markers, to ensure that nobody else can. (My own will calls for my body to be cremated without ceremony and for my ashes to be thrown into any convenient refuse receptacle).
Perhaps, like me, the family members you refer to recognise the utter pointlessness of 'commemoration'?