Encore can charge whatever rake they want to, It's their business. It is my opinion and I suspect that their rake is higher because they only want certain type and caliber of players in their casinos and if rake is cheap, they'll be too many rif-rafs coming there and they don't want that.
You as the player don't have pay their rake. If it's too high, go play somewhere else. I see in the comments lots of complaints mostly about rake, but the encore poker rooms are always filled to the max, if it's so bad, why is it always busy?
Sounds to me like people go there to play and they only complain when they have a losing session. My advice, learn how to beat high rake structured games, start your game, go to encore infrequently or not at all or go play somewhere else entirely.