Why there is no temperature scale tied to normal human body temperature?
Why nobody used human body normal temperature as 0?

That has been done.
See Medical Thermometry and Human Temperature at page 12:

37° Centigrade scale
29.6° Reaumur
98.6° Fahrenheit
77° Walferdin's tetracentigrade
0° of the physiological scale

Then the physiological scale is further discussed starting on page 265, which includes a drawing of a physiological scale thermometer.

physiological 0 is placed in the centre of the drama, whose acts are health, sickness, and death