The more customers there are, the more money casinos make.
If I were a casino owner, I wouldn't ban citizens of countries where gambling is prohibited. They can easily access the site through VPNs. It also uses cryptocurrency for deposits and withdrawals.
Why would I ban people who want to gamble?
In normal circumstances, yes, the gambling casino wouldn't want to restrict any country. The primary goal of the casino owner is to maximize profit, and that comes as more gamblers play at the casino. However, sometimes there are legal and regulatory risks or Jurisdictional requirements in certain area and the casino owners has to comply to those rules.
Also, I do not know from where Spinly got the license, but most of the reputable gambling licenses like Curacao or Malta require the gambling casino to be compliant with international laws, not following them can shut down their business.