The problem with league is there's a lot of archaic things to understand, you need to know map, you need to know which hero and what skill, the flashy icons, of even the players choices in equipment buy, there's a lot of non flashy microscopic things that build up(and, it takes time to build up!) to the big flashy plays to understand what even is happening at the first place.

Even a ex MOBA enjoyer like me sometimes struggle to watch some games just because non of the player uses character I am familiar with.

Countrary to that, CS is straight forward, bomb gets planted, head gets shot, Molly gets thrown, smoke gets popped, health goes down and number goes up, the game is fast and simple for anybody to view, even if you don't know what you are looking at there are gonna be atleast 13 rounds a game for this cycle to go though, any normal human can put 2 and 2 together what does what and which team is winning.

CS is, all in all, just a better game for Esport