That was my understanding. Though I suppose very hot tea that irritates the esophageal lining by mild burning, could aggravate the effects of the tannins. IOW very hot black tea could well be worse than less hot black tea.
Possibly, I don’t know. I take my hot tea British, so I don’t worry about it. Otherwise I guzzle my iced black sweet tea like any other good Southern boy. I gave up coffee and tea for Lent and all I can say is Easter can’t get here fast enough! LOL!