If you look at https://coinmarketcap.com/rankings/exchanges/ you can see a totally different list of exchanges, by volume

1   BKEX   $1.853.079.348   
2   Binance   $1.377.939.113   
3   CoinTiger   $1.321.659.103
4   MXC      $1.318.079.985   
5   OKEx    $1.303.200.015

I believe those exchanges voluem data are mostly fake and manipulated.... there is no way to determine the real volume of all those exchanges..

Kucoin and Gate.io, from your list, and CoinTiger and MXC from CMC, do not have all that high volume, for sure.