Monster Hunter's community is founded on the more experience players guiding newer players in the art of hunting. Pretty sure the community would not be where it is today without this aspect.
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But the depth of gameplay in Monster Hunter is much greater than Zelda. You need to know some detailed stuff, but you also need enough skill to be able to act out what you've learned.
In Zelda the game relies more on action-based puzzles a lot of the time. Execution of the solution is often easier than figuring out what the solution should be - so maybe they want to leave some aspect of making people figure things out for themselves instead being able to have one player explain how to solve everything.
That's a weak excuse - the game
definitely should have voice chat, even if limited to people on your friend list. But I think communication in Monster Hunter is different (probably even more important) than it is in this game.
I also agree that whoever it is in Nintendo that hates voice chat needs to get over it or move on. Seriously. 2015 and Nintendo still won't do online voice chat? (Then again, if we can't have SwapNote what makes me think we could have voice chat?)