I think this comes from purely emotional perception of, well, life. And pure emotions are bad advisers more often than not. Rational view would be, no matter what religion (or lack thereof) - body after death is just a pile of fast decomposing organic material, nothing important neither for living nor deceased.

I have much more respect for some eastern religions like Zoroastrians or some Buddhists in Tibet/high Nepal who chop the bodies of their close ones and leave it to predators. That's a true expression of proper belief in their religions.

People can't stand sight of their close one decomposing (apart from some remote tribes who have mummies/skulls of ancestors around the house), some would even be properly traumatized, but yet there is some obscure need to have the same biological matter confined somewhere where they can come and feel 'connected' again. Wouldn't a photo/3D model/hologram of the person achieve the same?

I mean, I wouldn't care less if somebody brings some flowers to my grave or lights candles. Just remember me when convenient, some good experiences and I will be glad