I think the problem is not just if they will list the coin on their exchange platform or not. I think it's also how they will name it. We had some wallets like Xapo and bitpay, saying that they will name the B2x as BTC if it gains enough support. If some exchanges did the same thing it would be total chaos for new users. I don't like segwit2x, specially because of the way they are doing things (saying they are the true bitcoin so they don't need replay protection, etc)
Since this is just an attempt to take control over BTC, and they don't really care about anyone else, I think it's very important that these exchanges and some mining pools are already expressing their zero support. I don't think this is just talk, I think this is also a message to wallets like xapo and bitpay, and everyone who supports this takeover attempt.