Turkish government introduced a new law to require license for cryptocurrency exchanges operating in Turkey. It is because they are planning to bring tax for crypto trades. Binance Global does not offer offramp for Turkish residents already, however it has a local (different website) brand here "Binance TR" which allows you to offramp crypto pretty easily. They do not want to get fined because of violation of regulation, so they will stop marketing for Turkish users on Binance Global exchange.
By the way Minister of Finance explained that they won't restrict people from using global exchanges. I think they are just trying to keep volume in local exchanges, because it's obvious global exchanges will not help for taxation.