No country can eradicate gambling automatically and the matter the restriction is in the country gamblers will look for a way to gamble.
This is not true. There are countries that have strong laws against gambling and the citizens too can't gamble. The gambling policy is so strong that even with a VPN you cannot have access to any gambling site. Even in some countries where its national laws accepts gambling activity, some States in that country still prohibits gambling. What it means is that as long as you are in that State you are restricted from gambling.
And if you arrest them, they would tell you that gambling gave them money and you that have put the law have not given them anything so what is the need. So those laws have no water tight implementation.
Ideally, no individual is above the law. Where there is a strong law against gambling, the youths cannot gamble. The reason is simple, the youths are not stronger than the State apparatus which simply tells us that your argument would not hold water where the law against gambling is strong because the moment some youths are apprehended, others will desist.