Men do prostitute their bodies. Homosexual men buy male prostitutes all the time. In the city I live there is one street in Hollywood where female prostitutes walk and a parallel street where males prostitutes walk. However the primary people who use prostitutes are men.
Most men are heterosexual.
That's just the numbers. Hence there is more of a demand for females. But there is a minority of men who are homosexual, and those men use male prostitutes. Men do prostitute their bodies. Homosexual men buy male prostitutes all the time.