Decisions like that are not forced on the deceased, well not normally unless the family handling the last wishes refuses to grant them. In most cases the family whats to be able to say good by to the loved one in a fitting rite. Americans have traditionally said good bye to their deceased with an open casket so it is only fitting to have the deceased clothed. It is like there are traditional ways to celebrate a birthday, and traditional ways to honor a graduate, these are rites that have been practiced for decades, but not forced on anyone.
It is for dignity. Even cremated bodies are dressed.
I loved my grandma. I never saw her naughty bits. Thank you, lacy, lavender funeral dress.
I've always said that I'm just a lump of bad meat when I'm dead, so why would you put a lump of bad meat in fancy clothes, in a fancy box, with fancy shenanigans? Would you drive a lump of bad meat around in a limo? Nope. That's what being alive is for. I couldn't care less what you do with me once I kick the bucket. Don't waste money on dead things. There's a reason why we decompose and all... (Morbid? I dunno.)
Because some people have a hard time looking at the living in public without clothes, and I don't think they would do any better with naked dead people.
so that when the dead come back as zombies, you can still keep the PG rating and no get switched to 'R'