The game it’s self is kinda like a game of chess, very strategic. I’ve never played the actual game myself but have watched a few games here and there.
Like anything professional it takes a lot of skill and training to be world class at it. People watch because they are exerting a great deal of skill, technique and strategy playing.
It’s like a sport you don’t follow. You don’t get it at first, more you watch the more you pick up the minute details that make it really interesting.
I personally follow golf or basketball but I can definitely understand why people watch it. It’s similar to that but because it’s video games some people don’t get it. Not their fault (or yours, not having a dig) it’s just not their thing.