Since you seem genuinely curious why everyone considers Ezuri better than Kamahl, here's the quick answer:
Ezuri's cheaper, his protection is better, and elves are so incredibly powerful that there's really nothing "limiting" about playing elf tribal.
The long answer is a bit more complex. For starters, it depends on what kind of Ezuri deck you're talking about. Typically, if you're arguing power levels, combo archetypes are more powerful than aggro strategies, so I'm going to assume that both decks intend to go infinite and kill each opponent with a single creature or dump their mana into a win condition.
So, Ezuri is cheaper. That's important because you often want to play Ezuri before elves that are important to your combo. He can't stop all forms of removal, but having
regenerate on key pieces for G is a pretty good deal. There are a small number of situations in which you have exactly enough mana to play Ezuri before dumping your combo and going for a win. Kamahl's cost doesn't really matter in his deck because he doesn't offer protection, just
mutual destruction. It's not nothing, but it only stops symmetrical board wipes. Ezuri can come down early to protect mana dorks for chump blocking, avoiding targeted removal, etc...
Next, Ezuri's protection is better. Like mentioned before, Kamahl only serves as a deterrent, not actual protection. Plus, he has to be out before you can combo off to protect your board, meaning you've had to shell out 4GG when you didn't have infinite mana and almost certainly had other things you'd like to cast. Ezuri's
regenerate doesn't cover everything by any means, but it's a great deal better in most situations.
As far as build options go, yeah, Ezuri's got elves. That's about it. Since that being a good or bad thing is completely subjective (as elves are perfectly viable and really only hindered by being mostly mono green), I don't really see a need to argue here. I like elves. Other people like elves. Some don't like elves. It's an opinion.
For what Kamahl can give you outside of elves... who cares? Ezuri doesn't have to play solely elves. My list has
Wirewood Symbiote,
Craterhoof Behemoth, and
Temur Sabertooth. Yeah, most of the deck is elves because they're particularly synergistic, but there's also nothing I'm really missing out on.
Ant Queen doesn't do anything because if I'm attacking with an infinite/infinite creature with trample, I only need one creature. You can do different go wide variations with Kamahl than just elf tribal with lords, but those are objectively weaker. If you don't care about the deck's power, then Ezuri can function as a voltron commander who only buffs himself; the point is, Ezuri doesn't really restrict the deck's power compared to Kamahl.
You mentioned uncommon commanders being harder to play against. That's only really true if you play with randoms or only play the deck once. In my experience, most people play with regular groups, so that extra novelty doesn't do much after the first few games. Also, unless your combo pieces and other parts of your strategy are similarly rare, no one's going to be fooled by Kamahl running the same
Umbral Mantle combo that other infinite mana green decks run.
So, to sum up, Ezuri is a better commander for the infinite mana into win strategy. If you like Kamahl better, great. If you think he's more powerful, that's perfectly fine too, but I'd be interested to hear why. Also, this was a great deal more than I expected to say on the subject, so I apologize for the wall of text.