Exchanges charge very little for their services. I think that's acceptable.
You realize that cryptocurrency exchanges are the only type of exchange that charge percent commissions, right? Conventional stock/commodities broker-dealers always charge flat fees on transactions. Exchanges have made a
killing off naive cryptocurrency traders and investors since inception. It's still incredible to me how little people complain about trading fees vs. other markets. Robinhood may encourage some industry change there, as they've now introduced zero-fee trading.
If you create some product that millions of people need, you also have the opportunity to become a millionaire. It seems to me that such accusations are a manifestation of human greed.
This discussion isn't about profiting from developing a good trading engine and designing/marketing a great exchange. It's about profiting from market manipulation and basically extorting altcoin developers into lining an exchange's pockets (under threat of de-listing). And if coins that were listed before such ongoing fee policies were instituted are subject to them now, that's
really grimy.
But exchanges on the whole aren't exactly known for being honorable. What else is new? Cash grabs all around.