and I am telling you that I can't play a game that doesn't respects the logic
CS has its own logic. It always has. Since 1999. And it loving works. Its competitive scene is a testament to that.
what's the problem with "casual" servers?
Because you're not actually learning the game that way. Casual servers may be a decent environment to learn the barebones basics of the game, but the game and the economy of a match are balanced around 5v5 play.
Perhaps the way competitive CS is played is not the exact way the two original creators "meant" for it to be played, but over 15 years it's widely accepted as the
way the game is actually played.Now learn to shoot.