I think we're talking at cross purposes.
A) The MC initially first and foremost wants to be a Friend, not a Lover, to Chika.... but the OP's reaction demonstrates their view of what they want the MC to do... and because they cannot they will not play. That is NOT romantic... that is just interpersonal relationships... and if you meet someone you like, think good things of, and try to be a friend to and support for, and then you cease because they're a hooker... that's pretty petty, low in fact.
B) No one can say not wanting to continue with a romantic relationship with someone who IS, it turns out, a hooker... is wrong. We all have Red Lines.... BUT... even then, it comes down to HOW. You can be sympathetic, understanding, gentle, and kind, even if you have to be firm on the NO. Or you can be a C U Next Tuesday. The OP's reaction definitely makes me think they'd be the latter.
Either way, in either case, this is WAY UNCOOL, and the problem of the person, not their hooker once friend.