That's because it's what give them more money. Influencers across web forget that destroying the mindset of potential gamblers will cause more harm to the market than good. Soon enough just like on this thread, influencers will most likely get bad reviews with their careless policy of advertising. Enough to drop the rate people tend to value products or services advertised by influencers. Which is not a good sign for any business. it's important to level down every steps made on the internet to help make a better community both online and offline. Assuming those kids are being taken on detailed online teaching process on responsible gambling.
When there is so much money in the influencer and gambling business model, there are some people who do not care if some type of advertising can harm Children or young people who are minors , because they only care that enter your Platform and play , but you have to be more Careful, more cautious, something that many people who have their child and don't do it is also valid, is to verify, guide and be aware of them at all times because they are minors of age, then it is also their fault for neglecting these things, Telephones, social networks, computers, they should not have as much access.