House edge is there to protect the interest of the house much more than the interest of the gambler this is so that gamblers stand the chance to only win the amount that their luck permits them to win and most times, one needs to look out for ways to prepare your mind that winning in gambling only occurs via luck and nothing else so while gambling never expects a winning.
The problem most people have is they think that they can apply the same method they use in betting, gambling works differently because of the house edge, just like what you said people should always their mind to lose when gambling on casino games. It's a waste of time to come up with winning strategies when playing games like black jack or slot games. Some gamblers even try to use mathematical tactics but these things don't really work as planned.