The article says only 2 out of the 25.
“Most of these pairs’ actual volume is under 1% of their reported volume on CMC. We noted only 2 out of the top 25 pairs not to be grossly wash trading their volume, Binance and Bitfinex.”
Well its all for the media games though. Even if we believe it or not, nothing will ever change to it, bots are being used to trade by pro who bought trading EA. This includes the arbitrage bots. I think it also happen on other markets like the stock and FOREX.