Ofcourse.. The gambling sites need to make a profit somehow.. They cannot only rely on the stupid decissions the players make. They need to guarantee an income to stay operational.
It is quite risky to run a gambling site. If a big roller comes along and wins in the first bets and decides to cash out, the casino faces insolvency quickly.
Exactly, a gambling site has to make a living, too.
They have bills to pay, like servers, maybe employees.
If they had a 0% house edge that would mean they give the people as much as they take from them.
This would drive them into bankrupt relatively soon. Maybe that is why they don't exist. Those who tried didn't make it.