A game shouldn't be criticized for being too easy if it fits the game. Mario and Pokemon both appeal to casuals, but can up the difficulty to satisfy those wanting a challenge.
The only exception is if it's a game directed towards a mature fanbase. For instance, no one would enjoy God of War if you had 10x as much health and the opponents were flatout idiots.
At the same time, a game can't just be hard for the sake of it. If a Mario game had places on the ground that'd automatically kill you, it'd probably be a hard game, but it wouldn't make it more enjoyable.
You have to see the context of the game honestly. It either is or isn't a fair piece of criticism







