Why?
If you read Rousseau he will explain it. Not that you will like or agree his take.
“If you read Roussea”
No, thanks. Prefer to read the originals.
Speaking of...
The Leader of the Democrats
Now let us examine Rousseau on this subject. This writer on public affairs is the supreme authority of the democrats. And although he bases the social structure upon the will of the people, he has, to a greater extent than anyone else, completely accepted the theory of the total inertness of mankind in the presence of the legislators:
http://bastiat.org/en/the_law.html