The government is taking this as an opportunity to increase the tax and the problem is that they will be using the pandemic as an excuse to increase the tax
If the country is really got heavily affected by the pandemic, it's just reasonable to increase tax on some performing industries amid the pandemic. Gambling is no doubt one of the top-performing industries so to consider them adding some tax to them just makes sense.
However, it's not just about the increase but that 20% tax is to encourage other gamblers to gamble as for sure if the casino operations will face a much higher tax than usual, they might pass some fees increase on their bettors.
In the long run, let's see if this planned of government is really effective to reduce the gambling activity in their country.