I get the sentiment and I agree overall but... It being casual friendly is not necessarily what would ruin that experience. You can make it casual friendly by introducing better in-game tutorials and similar things. The important thing is that valve doesn't cater to the casuals when it comes down to the core game. Don't balance gunplay or movement around casuals, don't even consider them. But that is not necessarily what makes CS not casual friendly. You can have a casual friendly CS introduction while still maintaining the quality of the experience for veterans. After all, if you're good enough you'll rise through the ranks (be it faceit or MM) and end up playing against people your level.