Well, i think we can't blame CMC because they show what is actually happened although it is "fake volume". Maybe those exchanges only want to attract people so people their site. But i think people for now already know which have fake volume, or maybe real volume. Or if they really doubt want to use the other exchanges or not, they can see people's review in here.
We can't blame coinmarketcap fully because the data on the trading volumes of the exchanges are not theirs to know and gather. But they could be stricter than they are right now and require trading platforms to prove that the volumes they are submitting are real volumes and not fake ones. CMC has to initiate something on this because this is getting rampant. CMC cannot just accept whatever volume data is submitted because if that is so a shitty exchange might suddenly submit that its 24-hour volume is reaching 1 trillion.
I actually don't know what to be the system, but maybe it is automatically updated in CMC. If want to strict about what exchanges can listed in there, it will be hard. Of course site like CMC need cost to maintain their site, and they need income from it. And then, maybe it is something that iresistable. Something that we can't do anything which is already there, and we just need to make research by ourself.