Earlier quoted context omitted.
Perhaps 15C is a typo? That is perfectly comfortable even at 100% RH + no air movement.
nope, no typo. 15C+100RH+no convection = you just die in a few hours.
But if you mean no forced convection, that's just not the case. You can survive at wetbulb temperatures in excess of 30 C, which means 30 C + 100% RH. Hell, my house right now is at about 25 C drybulb and 18 C wetbulb, which from the perspective of evaporative heat transfer is identical to 18 C with 100% RH, so I should be dying any minute. See you on the other side!