Many of those exchanges are shady and we know it (scam devs and whales cooperating ICO), but cannot call it scam if we don't have hard evidence. And if we have we must create topic in scam acquisitions and then moderator or administrator (or green trusted members), will gave him red trust..https://bitcointalk.org/index.php?action=trust;u=220467
So everyone then can see that they are scammers.
This is right way, everything else can be called trolling or fud..