I don’t disrespect the dead (not conscious).
To be completely serious, the only ethical reason for caring about the dead in any way is that there are living, conscious people that care about their memory and it would upset them. Otherwise there'd be zero reason to treat the dead with any more respect than other biological waste.
All the other parts are normal and practical (why waste time or energy bothering animals or insects if you have no business in them? that hurts the ecosystem for no reason; why destroy your own useful property?), but if there was no ethical reason for not "disrespecting" the dead then we should, as a matter of policy, turn it all into fertilizer and put the unusable parts into a trash compactor so that no precious land or resources are wasted on cemeteries and shit.
You can disagree with that, but I don't see a way to make an actual rational argument against it without invoking consciousness one way or another.
Just to be clear I don't deride people who treat dead with reverence, you do you, although I think we could have a discussion about how much space is taken by burial grounds and the frankly gauche nature of some of the tombstones.
Like look how much space this random municipal cemetery in Warsaw takes:
That's bigger than some living districts. And for what?
Like do we really need this system where each family has to buy a plot of land and spend a truckload of money on a big stone monument, with the implied social pressure of having the prettiest shiniest one because otherwise what, you don't love your dead ones enough?