Casual doesn't automatically mean you can't be decent at the game, some of my friends don't touch above Alliance raids and are really good at their jobs and the game in general.
Please stop this nonsense.
Being a casual is fine, you can be good at the game while only being a casual player who does alliance raids or whatever as their endgame.
Being good at the game does NOT mean you need to clear ultimates and savages.
Being good means you're able to perform well in the level of content you do, and know your main jobs well enough to complete said content.