I totally agree.  Blood sports like UFC can spread blood-borne illnesses such as HIV and hepatitis.  However, I am not aware if the fighters were ever tested for such infections prior to the fight.  I remember Dana White, president of UFC once dismissed one fighter because he had oral herpes.  I believe he did the right thing as oral herpes is highly contagious via skin to skin contact.  I don't believe it is discriminating to prohibit HIV-positive fighters from fighting.  In fact, I think it is the prudent thing to do.