You might as well tag them all. Every exchange has user complaints. Those users don't delete complaints after they have been resolved. Every legal exchange is subject to KYC laws - but customers consider it a scam if their funds are frozen. Users that have broken the law and have their funds seized will scream as loud or louder than those who have not broken the law and had their funds seized. Often an exchange cannot legally disclose why it is frozen.
Exchanges that are not subject to KYC are not in jurisdictions that comply with SEC rules and based in dubious countries. (So usually also exclude US citizens).
A lot of exchanges have dubious ownership structures - either in tax havens or hidden through trusts or shelf companies.
The exchanges that do comply with laws of the jurisdiction that they are in can seize your funds if requested by a Government and can pass your information to Government agencies.
Then there is wash trading and US tether... Has the exchange got Tether listed ?
Some exchanges offer low or no fee trading to coin devs. This allows the coin devs to trade their own coin giving the ability to create (fake) high volume without costing anything or a lot.
Source:
https://www.bti.live/reports-april2019/http://www.bti.live/exchanges/Bitcoin-Rigging Criminal Probe Focused on Tie to Tether