Actually, it’s not.
Believe what you want.
If you ask someone else to kill you it’s murder.
If you kill yourself it’s not murder - it’s suicide.
This has been the way civilized societies have viewed this for many many years.
If you want to kill yourself you are welcome to do so - only you can call the shots on that. Asking for someone else to kill you is morally wrong. Why would you want to burden another with your death? If you want to die then do it yourself - take responsibility for your own demise.
The thing is, it’s how it affects the person pulling the trigger or starting the drip or whatever. Suicide is the ultimate selfish act and asking someone else to participate makes it even more selfish. So the question is, does anything justify that degree of narcissistic selfishness?