How can someone buy BCH and think that he is buying BTC is beyond me, considering the huge difference in price. I mean, if you buy BCH thinking that you are actually buying BTC, but discounted for 97% (and not questioning yourself how can that be possible) you will have hard time in crypto. Hell, even on that website they make distinction between those two.
Its possible because their information misleading buyers. When a buyer want to buy bitcoin then he have to use credit/debit card. That's the reason the calculations will be in usd during buy process. So sometimes buyers just concentrate on USD amount instead of deeply look on btc/bch amount. So after bought eventually they received BCH instead of BTC. I can't recall the story but there is some claim about that buyers received BCH on his BTC address after bought.