There's now a UK petition to consider loot boxes and the like as gambling, and I see people in the U.S. trying to get similar ideas pushed out there.
People have begun to confuse gambling with risk.
Take booster packs for collecting card games.
You're buying cards for Magic the Gathering, Pokemon, Yu-Gi-Oh, or even Hearthstone in order to build up that perfect deck. You pay $4.99 for a pack, and there's no guarantee what you'll get. Some companies say there's a 20% chance of a rare, some just say "there's no guarantee."
Are card packs gambling?
No. It's not gambling because you are still guaranteed to get something. You're guaranteed the minimum offering of basic cards. You were told you would get X basic items and a chance for one to upgrade to a nicer item. Sure, they may not be what you want, but you still got something in return -- what you were promised. It's up to you to accept that what you get in return, at its basic level, should be worth the price of the pack.
The same applies to loot boxes. You buy one for any amount of value, whether with real money or in-game currency, and what you get is a risk that involves chance. However, even with the worst draws, you're guaranteed something in return. There is a predetermined and agreed upon exchange of value for value.
The ESRB recently told Kotaku:
While there’s an element of chance in these mechanics, the player is always guaranteed to receive in-game content (even if the player unfortunately receives something they don’t want). We think of it as a similar principle to collectible card games: Sometimes you’ll open a pack and get a brand new holographic card you’ve had your eye on for a while. But other times you’ll end up with a pack of cards you already have.
I get the argument. It's random luck -- that's where people mistakenly accuse this of being a gambling. You put in $4.99, and what you get out may be crap or it may be awesome. You may get the best card in the game, or your 20th basic card. It sucks. It influences the game's design, and not in a good way.
But gambling it is not.