We view people and animals as different. We have a long tradition of viewing people as different. We have pushed those limits somewhat with organ donation, but generally speaking, we don't break people down for spare parts. Most religions and corresponding cultures view people as made by God and having a small element of the diving. This is the reason people are considered better than animals, and the reason there are different requirements for veterinary vs human medicine. Same reason we eat animals without issue.
Maybe you disagree; we are each free to our respective opinions. But most people don't view humans as "just another kind of animal".
I guess this legislation is a way to rationally erode the obsolete emotional reasons for treating the human body as something special.
This legislation doesn't force anyone to be composted after their death. It gives a families and loved ones a new option, without taking away any options.
As such we haven't taken away anyone's options to treat humans specially, or however they wanted to be treated.
As long as it's safe and doesn't introduce significant negative externalities, I fail to see why not granting more choices would be a bad idea.
Dying humans are usually sick, old, or otherwise damaged, and are not slaughtered but die naturally, so e.g. they’re not bled out properly.
So even if it wasn’t dangerous due to diseases, it wouldn’t be palatable unless heavily processed down to the molecular level. At that point you basically get bonemeal, the same stuff we make from animal carcasses, and used as a fertilizer or food supplement for livestock.
Also, why not slaughter humans for food when they are younger and better eating? Why do we treat humans any different than any other animal?