I’ll try to answer:
When LE find dead bodies, they can often take clues from the body as to who the killer might be. For example, if a body is found buried with a blanket nicely wrapped around them, that might be a clue that person who put them there had some kind of love (“love”) for them.
A body found half naked in a dumpster bin is more likely to have been killed by a stranger with no connection to the victim.
A very simplified explanation, but what I’m trying to say is disposal of the bodies can somewhat be seen as an indication of how the killer who put them there felt about them.
We bury or otherwise treat our loved ones with care and respect when they die. We hold a funeral, we choose a casket or an urn, we pick flowers, their clothes, items for them to be buried with. We might say prayers. In our society, human remains are treated with respect. We don’t just take them to the local refuse station and dump them in and say “oh well, they’re dead anyway”.
If he had buried them with their blankies, it might have shown he had some care and love still left in him despite what he did. Instead, he dumped them in vats of oil. It’s dirty and gross and almost impossible to wash off.
It comes of as very offensive to most of us who consider that human remains should be treated with respect.
For me, it says concealment was his number one goal.