You've never played CS if you think it has less of a learning curve than CoH2 does. Sure, you can just jump in and deathmatch easily, but competitive play is very difficult to get into and excel at. In spite of that, CSGO regularly has 100,000+ people searching for and playing competitive games simultaneously. These are exactly the sorts of people who would be willing to analyze their play for improvement and read online about it in their spare time.
Difficulty has nothing to do with it; as someone who has played both, CSGO is just a more gratifying experience. It involves a high degree of mechanical skill and a number of layers of strategic play that aren't immediately apparent, and even when you lose you feel a strong sense of accomplishment if you played well personally. CoH2 doesn't really have any of those (mechanical skill, layers of strategy, or accomplishment when you lose), some of which is the fault of the RTS genre while others are faults of the game's design.
