They are not gambling in the legal sense. Gambling requires the potential for monetary loss. Buying random items is not gambling. If that was the case then buying hockey cards as a kid is gambling. Same with Pokemon cards. You are buying a product and you know exactly what you are going to get: 3 random items. You are fully aware that you are buying 3 items that could be anything. You did not lose any money, you got exactly what you purchased.

Apply this logic to anything else. X of the month clubs, "grab bags" in stores, card packs. You know exactly what you are getting, which is random items.

When I bought Pokemon cards as a kid, I got 5 random cards in a pack. That isn't gambling. I paid for 5 random cards. Just because all 5 cards I got were really common and not what I wanted doesn't change that fact. I paid for 5 cards, and 5 cards is exactly what I got.

If you actually want to stop loot boxes for existing, stop calling them gambling. They are not gambling in the legal sense. You bought random items, and got exactly what you paid for.