Most of the countries actually putting bans on gambling are for religious reasons and that's why it's mostly the middle east region although it's not entirely pin on those areas but I think you get the picture. Other countries are actually utilizing the massive gambling industry which is something that the government are well known for as they always exploit situation to their benefits and one way they achieve this is by taxing the gambling industry which active initiative towards this.
Yes, many countries still keep gambling illegal considering religious issues. However, the way gambling is being adopted nowadays. Even though the government has banned gambling, people access it in various ways. Crypto casinos can be accessed even in countries where gambling is illegal, and since gambling is played with crypto here, the government cannot do any kind of tracking. Many also access them using VPNs. However, officially, gambling has been kept illegal in most middle east countries considering the economic condition of the country and religious issues.