Like any thing else if you don't like change it, Rule 0. I see the long rest as a period of recuperation so not necessarily 100% sleep but a combination of activities that is abstracted into a period of time that help you get over the previous days hurts, stresses, and resource drain. It's no more illogical to me than you can only do 1 long rest per 24 hour period but it does provide a balance point to resources.
"A long rest is a peroid of extended downtime, at least 8 hours long, during which a character sleeps or performs light activity."
Assume a human does sleep 7 hours then spends 1 hour on eating and preparing.
An elf meditates for 4 hours, instead of sleeping.
So you want to tell me that the elf has to spend 4 hours on eating or other light activities to get the same benefit as a human?
Its not logical. Its a decision made for balancing purpose. Nothing else.