If you need rape to pull the romance elements in your manga together, you just don't know how to write good stories with a good plot and good characters. That's that. Rape is unnecessary when you aim for romance and when you advertise your manga as a romance and it's filled to the brim with rape, it defeats the whole purpose of the manga being romance because rape isn't romantic in the first place. If you aim for a thriller, horror, drama genre without having a romance aspect, maybe rape could work whithin certain settings. But this is just distasteful.
Who is insulting your intelligence? I'm not the one throwing a fit because someone said that if you cannot pull the romance aspect of your manga without rape at all you just don't know how to write a good plot and characters. Take the rape out of this story and tell me, would the story still be "good" in your standards? Probably not. It would feel like a wet piece of bred. Now with the rape, this manga just feels like moist bread because the writing isn't good either.
Authors aren't free of criticism and if people are displeased with a story they have every rights to voice it. If they had put more time into building an actual story and develop their characters rather than putting time and effort on rape, it would have been beneficial to the story overall and it would of had alot more backbone than it does.
If you can't separate unreasonable irrational thought from actions, you're no help to society, rape victims, courts of law, and you certainly aren't able to validly critique this work. If all you've got is "It has rape. ewww" then consider it already said by others and kindly refrain from adding to the hateful remarks here.