Given the high volatility of some coins, this sounds quite correct. because the exchanges want to make money, and not work in the red, and you can understand them in this, although some other exchanges clearly go overboard.
No, why should I understand if they take withdrawal fees that are twenty times higher than the actual fees it would cost to send a certain coin from A to B?
There is no reason to understand that. It is rip off, and rip off should not be tolerated!