Why do they say hep c is only likely to occur through sexual intercourse when hiv is present?
When I say 'they', not sure what I even mean!

Hep c is transmitted by coming into contact with blood or sexual bodily fluids. What I mean about coming into contact is through mucous membranes such as the mouth, anus, vaginal tract, or urethral opening at the end of the penis or vagina and open areas of the skin such as lacerations, abrasions, torn cuticle, etc.