EMH is actually a hypothesis (not a theory) that arises from non-arbitrage models. It's not meant to describe the real world, although it's thought-provoking to look at how "efficient" real markets are, so people like to characterize and "test" the EMH in its various forms. How markets fail to be "efficient" is often quite instructive for practical purposes.

For pedagogical purposes, I think it's a really good simplified and ideal illustrative model, until you learn the more axiomatic derivations of no-arbitrage (the arrow-debreau stuff). From your other posts, I gathered that you're not beyond undergrad studies in economics - you'll likely learn about the more complex models when you reach a more advanced and rigorous stage, if you pursue the theoretical path.

If I were you, I wouldn't be too concerned about others arguing about the EMH - without the proper foundations, you won't understand them beyond a superficial level.

Not to mention that it's popular for the less educated to bitch about the EMH, probably because it's an English acronym with commonly used words. I've almost never heard laymen talk about how unrealistic the nash equilibrium is (: