Is this true? If so, that makes the review system worthless, but it does explain why there are no persistent negative reviews on any of the exchanges you've listed.
If this is indeed true, can you publish this as a warning in bold on the review page? It seems misleading to omit this.
This needs to be changed asap and it's impossible that rating system is showing only positive feedback from all customers, that is not happening even for ideal exchanges.
From my observation I could only found total of 9 exchanges with negative feedback from 245 exchanges, and most negatives are for big centralized exchanges (Kraken, Binance, Okex, Bittrex, Hitbtc) that don't care to reply anything.
This is unacceptable, and in my opinion openchange deserves negative feedback because they don't want to refund coins without kyc.