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.
True with the exception of a few top honest exchanges like Binance, most of the volume reported from most exchanges is fake. There is alot of wash trading going on to keep the exchanges on top of the marketcap ranks.
For example i have first had experience from Okex when trading. Lots of bots in action trying to hype up the volume.