It's really hard to effectively communicate comp to purely casual players for a bunch of reasons. There are people who either have a ton of misconceptions about comp (there are a ton of people who think the weapon ban list is >50% of unlocks and stuff of that nature) or people with large followings making hour-long videos ranting about how the existence of comp players is a burden to the game and comp players should all go to hell or overwatch.
Most of the time people don't know comp exists, and while the traditional response has been to look at valve, I'm happy that there seems to be more motivation recently within the community to actually improve things.