>For each withdrawal, a flat fee is paid by users to cover the transaction costs of moving the cryptocurrency out of their Binance account.

It says a flat fee not a percentage. If you look at another chain ADA, for example, the fee is 0.8. I seriously doubt Binance is charging 80% of the value to make and ADA transaction. No one would use Binance if that was the case.

I use coinbase and that only charges the network transactions fee. They also wrap multiple outputs into a single transaction so if you're sending from coinbase you're splitting the network fee with many other senders.