It is a long known practice of exchanges and cloud miners to keep airdrops and forks to themselves. They are arguing that the effort to distribute the tokens and make them available is very high.
For the listing procedure this might indeed be the case since the moment they introduce a token, they most likely also have to allow trading which incorporates some additional work to be done.
Also, any airdrop to a coin listed on Binance would open the door for it to be registered.
Still, I don´t believe that all the exchanges are not claiming the tokens themselves and add massive profit to their wallets. Directly distributing the tokens without starting any trading activities could be a solution.
For now, the only way to claim all the airdrops is in your wallet, and it is good that you inform people about this.