We aren't in control of those exchanges and what they do. Witnesses also aren't Steem officials/employees in any regard either, so most exchanges don't care about us or want to talk to us. While witnesses do everything within their power to encourage the growth of steem, we don't have the capacity to actually negotiate with these larger exchanges.

You can always use blocktrades.us (which is run by one of the witnesses), which doesn't require account creation.