It's not about "hand-wringing" or "defending the practice," it's about the loot-box system not fitting the legal definition of gambling so it's pointless to attack them that way.
Now if the loot-box system (or a particular iteration of it) is using similar psychological effects to unfairly coerce consumers into spending money there may be protection laws against it, especially if it is targeting vulnerable people or children.
Here's the UK's official legal stance on the matter;
Where the facility exists for players of video games to purchase a key to unlock a bundle containing an unknown quantity and value of in-game items as a prize, and where there are readily accessible opportunities to cash in or exchange those awarded in-game items for money or money’s worth, then these elements of the game are likely to be considered licensable gambling activities. In contrast, where prizes are restricted for use solely within the game, such in-game features would not be licensable gambling. The Gambling Commission is committed to working with the video game industry to prevent gambling-related harm related to their platforms.
Consumers are also protected by the Consumer Protection from Unfair Trading Regulations 2008. This includes a requirement on businesses not to subject anyone to misleading or aggressive marketing practices, or, for example, direct exhortation to buy products, such as games content, including in-game purchases such as loot boxes. The government is committed to ensuring that consumers are properly protected and that children’s vulnerability and inexperience is not exploited by aggressive commercial practices.