I've never heard a good argument against prostitution. The arguments that I hear are against trafficking, rape, child molestation; which are all non-sequiturs: true and valid statements that do not support the argument itself. Can anyone here argue against prostitution per se? I'll listen.
You've completely removed all the main "negatives" of prostitution, saying those aren't "real arguments."
While it's possible that heroin injection and prostitution may be done in a safe and clean way, the reality is extremely far from that in both cases.