I think this dice game itself is like that and very difficult to prove who is correct and who is wrong. It is purely depends on one's luck so instead of blaming any sites just don't play dice games for making money. Try to bet where you can guess results based on some calculation or knowledge.
It is pretty much the opposite of it. With the provably fair feature, the dice site can prove to users that the bets have not be modified, while the playes can prove if the site has rigged the bets.
What you said is correct than both players and house should be a winning equally but in reality only house will be winning at the end. That is something very difficult part to understand in dice game. I saw many times we can lose over 20 times continuously but I never win so many times continuously.
Nope I am not saying both players and the house should be winning equally. What I said is that "provably fair", as the name stands, give both side a way to prove the fairness of the game. House always wins in dice game in the long run because there is a house edge. For example with a 1% house edge, the players will only have 49.5% chance to win their x2 bets and have 50.5% chance to lose.