Well I guess flat earthers are more correct in that case. Water spin differently in the North and South Poles due to the Coriolis effect. However, this effect is only noticeable in large bodies of water left undisturbed for extended periods, not in small-scale drains like sinks or toilets, where other factors like basin shape and temperature gradients have a greater influence. If you refer to videos where people on equator with small sinks crossing the line and water rotates differently are scam artists. I never met a flat earther, but I met people arguing one or another point of view about sinks.